feat: add model, instruction, voice_sample_gcs_uri, and consent_audio_gcs_uri to google_ces_app synthesize_speech_configs

[aiestaran]

Supports generative TTS configuration and voice cloning fields in google_ces_app.audio_processing_config.synthesize_speech_configs:

• model: TTS model used to synthesize audio (e.g. gemini-3.1-flash-tts-preview, default Chirp3-HD).
• instruction: Instruction used to synthesize speech when using a generative model.
• voice_sample_gcs_uri: GCS URI to audio sample for voice cloning.
• consent_audio_gcs_uri: GCS URI to consent audio for voice cloning.

API Reference: https://docs.cloud.google.com/gemini-enterprise-cx/cx-agent-studio/reference/rest/v1/projects.locations.apps#App.SynthesizeSpeechConfig

ces: added `model`, `instruction`, `voice_sample_gcs_uri`, and `consent_audio_gcs_uri` fields to `google_ces_app.audio_processing_config.synthesize_speech_configs`

[github-actions]

Googlers: For automatic test runs see go/terraform-auto-test-runs.

@rileykarson, a repository maintainer, has been assigned to review your changes. If you have not received review feedback within 2 business days, please leave a comment on this PR asking them to take a look.

You can help make sure that review is quick by doing a self-review and by running impacted tests locally.

[rileykarson]

@modular-magician reassign-reviewer @rileykarson

[modular-magician]

Hi there, I'm the Modular magician. I've detected the following information about your changes for commit 1d79f00:

Diff report

Your PR generated the following diffs in downstream repositories:

Repository	Diff Link	Changes
google provider	View Diff	5 files changed, 152 insertions(+), 10 deletions(-)
google-beta provider	View Diff	5 files changed, 152 insertions(+), 10 deletions(-)
terraform-google-conversion	View Diff	1 file changed, 44 insertions(+)
Open in Cloud Shell	View Diff	1 file changed, 4 insertions(+)

Test report

Analytics

Total Tests	Passed	Skipped	Affected
75	73	0	2

Affected Service Packages

• ces

Learn how VCR tests work

---

Step 1: Replaying Mode

Action taken

Found 2 affected test(s) by replaying old test recordings. Starting RECORDING based on the most recent commit.

Click here to see the affected tests

• TestAccCESApp_cesAppBasicExample
• TestAccCESApp_update

View the replaying VCR build log

---

Step 2: Recording Mode

Recording Mode	Replaying Rerun	Test Name
❌ Error · Log	-	TestAccCESApp_cesAppBasicExample
❌ Error · Log	-	TestAccCESApp_update

Caution

Issues requiring attention before PR completion

🔴 Initial Recording Failed: Some tests failed during the recording step. See the table above for details.

Please address these issues to complete your PR. If you believe these detections are incorrect or unrelated to your change, please raise the concern with your reviewer.

View the recording VCR build log or the debug logs folder for detailed results.

@aiestaran, @rileykarson VCR tests complete for 1d79f00!

[rileykarson]

Followed up about test error