[Go] [Google AI] Plugin tests fail

[kwjw]

When running tests on tip-of-tree:

$ go test ./plugins/googleai/ -key ${GOOGLE_GENAI_API_KEY}
--- FAIL: TestLive (2.59s)
    --- FAIL: TestLive/generate (0.31s)
        googleai_test.go:89: got "Napoleon was the Emperor of **France**.\n", expecting "France"
        googleai_test.go:95: Empty usage stats ai.GenerationUsage{Custom:map[string]float64(nil), InputAudioFiles:0, InputCharacters:0, InputImages:0, InputTokens:9, InputVideos:0, OutputAudioFiles:0, OutputCharacters:0, OutputImages:0, OutputTokens:0, OutputVideos:0, TotalTokens:9}
    --- FAIL: TestLive/streaming (1.04s)
        googleai_test.go:127: Empty usage stats ai.GenerationUsage{Custom:map[string]float64(nil), InputAudioFiles:0, InputCharacters:0, InputImages:0, InputTokens:9, InputVideos:0, OutputAudioFiles:0, OutputCharacters:0, OutputImages:0, OutputTokens:0, OutputVideos:0, TotalTokens:9}
FAIL
FAIL    github.com/firebase/genkit/go/plugins/googleai  2.667s
FAIL

[kwjw]

Tests fail non-deterministically:

$ go test ./plugins/googleai/ -key ${GOOGLE_GENAI_API_KEY}
--- FAIL: TestLive (2.88s)
    --- FAIL: TestLive/generate (0.08s)
        googleai_test.go:84: googleapi: Error 503:
    --- FAIL: TestLive/streaming (1.04s)
        googleai_test.go:127: Empty usage stats ai.GenerationUsage{Custom:map[string]float64(nil), InputAudioFiles:0, InputCharacters:0, InputImages:0, InputTokens:9, InputVideos:0, OutputAudioFiles:0, OutputCharacters:0, OutputImages:0, OutputTokens:0, OutputVideos:0, TotalTokens:9}
FAIL
FAIL    github.com/firebase/genkit/go/plugins/googleai  2.955s
FAIL

[kwjw]

Given that we're getting Error 503, we might want to add a retry with exponential back-off in the tests (and possibly in the core libraries?)