CLOUDP-285944: Add support for Flex Cluster to atlas cluster ls

# Dedicated Cluster
```
./bin/atlas cluster list -P prod
ID                         NAME         MDB VER   STATE
6756d725072a5702c704a0ad   ClusterM10   8.0.3     CREATING
~/workspace/mongodb-atlas-cli
```

# Flex Cluster
```
./bin/atlas cluster list -P prod --tier FLEX
ID                         NAME          MDB VER   STATE
6756d6f81633e20b114c96b9   ClusterFlex   8.0.3     IDLE
```

Author: andreaangiolillo

docs/command/atlas-clusters-list.txt

@@ -61,6 +61,10 @@ Options
      - string
      - false
      - Hexadecimal string that identifies the project to use. This option overrides the settings in the configuration file or environment variable.
+   * - --tier
+     - string
+     - false
+     - Tier for each data-bearing server in the cluster. To learn more about cluster tiers, see https://dochub.mongodb.org/core/cluster-tier-atlas.
 
 Inherited Options
 -----------------

internal/cli/clusters/list.go

@@ -25,12 +25,14 @@ import (
 	"github.com/mongodb/mongodb-atlas-cli/atlascli/internal/store"
 	"github.com/mongodb/mongodb-atlas-cli/atlascli/internal/usage"
 	"github.com/spf13/cobra"
+	atlasv2 "go.mongodb.org/atlas-sdk/v20241113001/admin"
 )
 
 type ListOpts struct {
 	cli.GlobalOpts
 	cli.OutputOpts
 	cli.ListOpts
+	tier  string
 	store store.ClusterLister
 }
 
@@ -47,6 +49,14 @@ var listTemplate = `ID	NAME	MDB VER	STATE{{range valueOrEmptySlice .Results}}
 `
 
 func (opts *ListOpts) Run() error {
+	if opts.tier == atlasFlex {
+		return opts.RunFlexCluster()
+	}
+
+	return opts.RunDedicatedCluster()
+}
+
+func (opts *ListOpts) RunDedicatedCluster() error {
 	listOpts := opts.NewAtlasListOptions()
 	r, err := opts.store.ProjectClusters(opts.ConfigProjectID(), listOpts)
 	if err != nil {
@@ -56,7 +66,27 @@ func (opts *ListOpts) Run() error {
 	return opts.Print(r)
 }
 
-// atlas cluster(s) list --projectId projectId [--page N] [--limit N].
+func (opts *ListOpts) RunFlexCluster() error {
+	r, err := opts.store.ListFlexClusters(opts.newListFlexClustersAPIParams())
+	if err != nil {
+		return err
+	}
+
+	return opts.Print(r)
+}
+
+func (opts *ListOpts) newListFlexClustersAPIParams() *atlasv2.ListFlexClustersApiParams {
+	includeCount := !opts.OmitCount
+	return &atlasv2.ListFlexClustersApiParams{
+		GroupId:      opts.ConfigProjectID(),
+		IncludeCount: &includeCount,
+		ItemsPerPage: &opts.ItemsPerPage,
+		PageNum:      &opts.PageNum,
+	}
+}
+
+// ListBuilder builds a cobra.Command that can run as:
+// atlas cluster(s) list --projectId projectId [--page N] [--limit N] [--tier tier].
 func ListBuilder() *cobra.Command {
 	opts := &ListOpts{}
 	cmd := &cobra.Command{
@@ -85,6 +115,7 @@ func ListBuilder() *cobra.Command {
 	cmd.Flags().IntVar(&opts.PageNum, flag.Page, cli.DefaultPage, usage.Page)
 	cmd.Flags().IntVar(&opts.ItemsPerPage, flag.Limit, cli.DefaultPageLimit, usage.Limit)
 	cmd.Flags().BoolVar(&opts.OmitCount, flag.OmitCount, false, usage.OmitCount)
+	cmd.Flags().StringVar(&opts.tier, flag.Tier, "", usage.Tier)
 
 	cmd.Flags().StringVar(&opts.ProjectID, flag.ProjectID, "", usage.ProjectID)
 	opts.AddOutputOptFlags(cmd)

internal/cli/clusters/list_test.go

@@ -23,10 +23,12 @@ import (
 	"github.com/mongodb/mongodb-atlas-cli/atlascli/internal/mocks"
 	"github.com/mongodb/mongodb-atlas-cli/atlascli/internal/pointer"
 	"github.com/mongodb/mongodb-atlas-cli/atlascli/internal/test"
+	"github.com/stretchr/testify/require"
 	atlasClustersPinned "go.mongodb.org/atlas-sdk/v20240530005/admin"
+	atlasv2 "go.mongodb.org/atlas-sdk/v20241113001/admin"
 )
 
-func TestList_Run(t *testing.T) {
+func TestList_RunDedicatedCluster(t *testing.T) {
 	ctrl := gomock.NewController(t)
 	mockStore := mocks.NewMockClusterLister(ctrl)
 
@@ -49,9 +51,34 @@ func TestList_Run(t *testing.T) {
 		Return(expected, nil).
 		Times(1)
 
-	if err := listOpts.Run(); err != nil {
-		t.Fatalf("Run() unexpected error: %v", err)
+	require.NoError(t, listOpts.Run())
+}
+
+func TestList_RunFlexCluster(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	mockStore := mocks.NewMockClusterLister(ctrl)
+
+	expected := &atlasv2.PaginatedFlexClusters20241113{
+		Results: &[]atlasv2.FlexClusterDescription20241113{
+			{
+				Name: pointer.Get("test"),
+				Id:   pointer.Get("123"),
+			},
+		},
 	}
+
+	listOpts := &ListOpts{
+		store: mockStore,
+		tier:  atlasFlex,
+	}
+
+	mockStore.
+		EXPECT().
+		ListFlexClusters(listOpts.newListFlexClustersAPIParams()).
+		Return(expected, nil).
+		Times(1)
+
+	require.NoError(t, listOpts.Run())
 }
 
 func TestListTemplate(t *testing.T) {