fix: Allow -latest model aliases in GoogleSearchTool

[hemasekhar-p]

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Link to Issue or Description of Change

1. Link to an existing issue (if applicable):

• Closes: GoogleSearchTool rejects valid -latest model aliases (e.g., gemini-flash-latest) #1203

2. Or, if no issue exists, describe the change:

If applicable, please follow the issue templates to provide as much detail as
possible.

Problem:
The GoogleSearchTool checks model.startsWith("gemini-2") || model.startsWith("gemini-3"), which rejects all -latest model aliases (gemini-flash-latest, gemini-pro-latest, gemini-flash-lite-latest).

Solution:
Introduced the isSupportedModel helper method to allow model names ending with -latest in addition to existing models.

Testing Plan

Added unit tests to ensure missing models return the expected IllegalArgumentException and that -latest aliases are correctly accepted.

Unit Tests:

• I have added or updated unit tests for my change.
• All unit tests pass locally.

The following test cases were added to BaseToolTest:

processLlmRequestWithLatestAliasAddsToolToConfig: Verifies that models ending in -latest are accepted and configured correctly.

processLlmRequestWithUnsupportedModelReturnsError: Verifies rejection of invalid model strings.

processLlmRequest_WithNullModel_ReturnsError: Verifies that a null model input does not crash and throws an IllegalArgumentException as expected.

Checklist

• I have read the CONTRIBUTING.md document.
• My pull request contains a single commit.
• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• I have added tests that prove my fix is effective or that my feature works.
• New and existing unit tests pass locally with my changes.
• I have manually tested my changes end-to-end.
• Any dependent changes have been merged and published in downstream modules.

[hemasekhar-p]

@anFatum, Please have a look into it.

[tilgalas]

thanks for the PR - overall LGTM with one comment