fix(flutter-freezed): exported Patterns for advanced configuration

[Parables]

This closes #319

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

Screenshots/Sandbox (if appropriate/relevant):

Adding links to sandbox or providing screenshots can help us understand more about this PR and take
action on it as appropriate

How Has This Been Tested?

This PR doesn't change any existing functionality.
All existing tests passed.

Checklist:

• I have followed the
  CONTRIBUTING doc and the
  style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• [ x] I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[changeset-bot]

🦋 Changeset detected

Latest commit: 1c7a950

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@graphql-codegen/flutter-freezed	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR

[Parables]

@saihaj @Urigo please help me get this PR merged cause its long overdue.

Thanks very much for everything

[saihaj]

Thank you!