refactor: Use TypeDefinition.moduleAlias and remove moduleAlias from other definitions

[klkucaj]

Description:
This refactor standardizes the use of the moduleAlias field by consolidating it within the TypeDefinition structure. The moduleAlias field, which was already present, has been updated with additional checks and logic to improve its functionality across the codebase. The field has been removed from all other definitions to simplify and centralize its usage.

Changes include:

• Consolidated the moduleAlias field into TypeDefinition.
• Updated the moduleAlias getter to include new checks:
  • Added conditions to handle _projectRef and _packageRef prefixes.
• Removed moduleAlias from all other related definitions.
• Updated relevant references and usages to align with the new structure.

Why this change?

• Ensures a single source of truth for the moduleAlias field.
• Improves code maintainability and reduces redundancy.

Closes: #3131

Pre-launch Checklist

• I read the Contribute page and followed the process outlined there for submitting PRs.
• This update contains only one single feature or bug fix and nothing else. (If you are submitting multiple fixes, please make multiple PRs.)
• I read and followed the Dart Style Guide and formatted the code with dart format.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///), and made sure that the documentation follows the same style as other Serverpod documentation. I checked spelling and grammar.
• I added new tests to check the change I am making.
• All existing and new tests are passing.
• Any breaking changes are documented below.

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Breaking changes

If you have done any breaking changes, make sure to outline them here, so that they can be included in the notes for the next release.

[Isakdl]

LGTM, just one little nit!