Change Dialogflow Agent test to use separate project to avoid issues during parallel testing

[shang-jason]

For fixing parallel testing issues mentioned in hashicorp/terraform-provider-google#24678

[github-actions]

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[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes:

Diff report

Your PR generated some diffs in downstreams - here they are.

google provider: Diff ( 2 files changed, 49 insertions(+), 5 deletions(-))
google-beta provider: Diff ( 2 files changed, 49 insertions(+), 5 deletions(-))

[modular-magician]

Tests analytics

Total tests: 16
Passed tests: 15
Skipped tests: 0
Affected tests: 1

Click here to see the affected service packages

• dialogflow

Action taken

Found 1 affected test(s) by replaying old test recordings. Starting RECORDING based on the most recent commit. Click here to see the affected tests

• TestAccDialogflowAgent_dialogflowAgentFullExample

Get to know how VCR tests work

[modular-magician]

🟢 Tests passed during RECORDING mode:
TestAccDialogflowAgent_dialogflowAgentFullExample [Debug log]

🟢 No issues found for passed tests after REPLAYING rerun.

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🟢 All tests passed!

View the build log or the debug log for each test