Test

Add a doc-import into template_data.dart to resolve 'GeneratorBackend… #4414

Job	Run time
test (ubuntu-latest, dev, main)	5m 10s
test (ubuntu-latest, dev, flutter)	12m 12s
test (ubuntu-latest, dev, packages)	1m 16s
test (ubuntu-latest, dev, sdk-docs)	1m 17s
test (ubuntu-latest, stable, main)	5m 20s
test (ubuntu-latest, stable, packages)	1m 17s
test (macos-latest, dev, main)	4m 43s
test (windows-latest, dev, main)	4m 33s
	35m 48s

Provide feedback