feat: add gemini-2.5-flash-preview-05-20 models #7529

Job	Run time
check-translations	50s
compile	1m 29s
knip	53s
check-openrouter-api-key	1s
test-extension (ubuntu-latest)	2m 53s
test-webview (ubuntu-latest)	1m 2s
test-extension (windows-latest)	3m 36s
test-webview (windows-latest)	2m 49s
integration-test	0s
unit-test	1s
	13m 34s

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