fix(merge): Don't merge/override arguments for repeatable directives

[wKich]

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Description

According to GraphQL Spec directives might be marked as repeatable, that means a GraphQL node might have more than one the same directive with different set of arguments. Currently @graphql-tools/merge package while merging doesn't respect repeatable directives and as a result overrides multiple same directives on one node and keeps only the last one. Which doesn't happen if directives declared in a node that isn't overridden. By this PR I merge directives definitions first and then use isRepeatable flag to merge directives properly.

Related #4767

Type of change

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

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

• Test A
• Test B

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
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests and linter rules pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Further comments

If this is a relatively large or complex change, kick off the discussion by explaining why you chose the solution you did and what alternatives you considered, etc...

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🦋 Changeset detected

Latest commit: 0deee32

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

This PR includes changesets to release 1 package

Name	Type
@graphql-tools/merge	Patch

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[ardatan]

Thanks @wKich !