fix(core): inject migration should treat @Attribute as optional

[RussellSprouts]

The @Attribute decorator will inject null if a host attribute is missing, but inject(new HostAttributeToken(...)) will throw a no provider error. We should set {optional: true} when migrating an @Attribute decorator. Also allow nonNullableOptional to add ! to those declarations if enabled.

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[pkozlowski-opensource]

This PR was merged into the repository by commit 0162ceb.

The changes were merged into the following branches: main

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