Fix tests

[markmcd]

Fix tests across all languages

• Use GEMINI_API_KEY instead of GOOGLE_API_KEY everywhere (except Java, which has it mapped)
• JDK 21 -> 24
• Python unittest framework
• Increase Go test timeout so it runs
• Use pinned action deps

Also removing the "environment" setup, it's too much overhead. Using pull_request instead.

[gemini-code-assist]

Code Review

This pull request removes the environment variable check for GEMINI_API_KEY and a comment in javascript/grounding.js. The reviewer advises against this change, noting that removing the validation prevents the application from failing fast, which makes debugging more difficult due to less descriptive errors. It is recommended to retain the check.

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javascript/grounding.js (21-23)

Removing the check for GEMINI_API_KEY prevents the application from failing fast when the required environment variable is missing. Without this validation, the SDK initialization or subsequent API calls will fail with a less descriptive error, making debugging more difficult for users running this example. It is highly recommended to retain this check to ensure a clear and immediate error message is presented.

[soosung80]

lgtm