Fix missing resolved import handling.

[davidmorgan]

Fix #4064

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PR Health

Changelog Entry ✔️

Package	Changed Files

Changes to files need to be accounted for in their respective changelogs.

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Package publishing

Package	Version	Status	Publish tag (post-merge)
package:build	2.5.4	ready to publish	build-v2.5.4
package:build_config	1.1.3-wip	WIP (no publish necessary)
package:build_daemon	4.0.5-wip	WIP (no publish necessary)
package:build_modules	5.0.13	already published at pub.dev
package:build_resolvers	2.5.4	ready to publish	build_resolvers-v2.5.4
package:build_runner	2.5.4	ready to publish	build_runner-v2.5.4
package:build_runner_core	9.1.2	ready to publish	build_runner_core-v9.1.2
package:build_test	3.1.1	already published at pub.dev
package:build_web_compilers	4.1.5	already published at pub.dev
package:scratch_space	1.0.3-wip	WIP (no publish necessary)

Documentation at https://github.com/dart-lang/ecosystem/wiki/Publishing-automation.