Fix stale Gemini CLI e2e test assertions after removing /env/* keys

[yrobla]

Context

Identified in PR #5142 review by @JAORMX (comment on test/e2e/cli_llm_all_clients_test.go line 452).

Problem

After PR #5142 dropped /env/GOOGLE_GEMINI_BASE_URL from Gemini CLI's LLMGatewayKeys, the e2e test still asserts that pointer is present:

geminiURL, found := jsonPointerGet(geminiAfter, "/env/GOOGLE_GEMINI_BASE_URL")
Expect(found).To(BeTrue(), ...)
Expect(geminiURL).To(Equal(...))

This assertion will fail when the e2e suite runs because we no longer write that key.

Fix

Replace with an assertion on the only key we still patch — /security/auth/selectedType:

selectedType, found := jsonPointerGet(geminiAfter, "/security/auth/selectedType")
Expect(found).To(BeTrue(),
    "gemini-cli /security/auth/selectedType should still be present after claude-code teardown")
Expect(selectedType).To(Equal("gemini-api-key"),
    "gemini-cli selectedType should still be 'gemini-api-key' after claude-code teardown")

Also update any other e2e expectations that reference GOOGLE_GEMINI_BASE_URL for Gemini CLI.

References

• PR Correct Gemini CLI LLM gateway config to proxy mode #5142 review comment by @JAORMX on test/e2e/cli_llm_all_clients_test.go:452
• PR Correct Gemini CLI LLM gateway config to proxy mode #5142 review comment by Copilot on test/e2e/cli_llm_all_clients_test.go (comment accuracy)

[yrobla]

No longer needed. The issue was filed against an intermediate version of #5142 that had dropped /env/GOOGLE_GEMINI_BASE_URL from Gemini CLI's LLMGatewayKeys. The final merged commit restored the key, so config.go still writes it and the e2e assertion at line 458 is correct and consistent with production.