ci: skip codecov for dependabot PRs

Dependabot PRs fail codecov upload with "Token required because branch
is protected" error. This change modifies the test-and-codecov job
condition to exclude dependabot PRs while maintaining normal codecov
functionality for all other contributors.

Signed-off-by: Vibhu Prashar <vibhu.sharma2929@gmail.com>

Author: vprashar2929

.github/workflows/pr-checks.yaml

@@ -99,7 +99,7 @@ jobs:
 
   test-and-codecov:
     needs: check-changes
-    if: needs.check-changes.outputs.changes == 'true'
+    if: needs.check-changes.outputs.changes == 'true' && github.actor != 'dependabot[bot]'
     permissions:
       contents: read
     uses: ./.github/workflows/test-and-codecov.yaml