export type to support isolatedModules

[cungminh2710]

Description

Re-exporting a type when the '--isolatedModules' flag is provided requires using 'export type'

Related # (issue)

Close #6773

Type of change

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

Checklist:

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

[changeset-bot[bot]]

🦋 Changeset detected

Latest commit: 53a60efc032b16f395fc56f9234f2d38c293ce98

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/typescript	Minor

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[dzearing]

@cungminh2710 Is there any progress on this?

[cungminh2710]

@dzearing hi there, i forgot to work on this. Will address some feedback soon this week

[cungminh2710]

@saihaj it's been a while. any chance to land this PR?