feat: enhance loading states in data loader hooks

[philibea]

Adds distinction between initial loading (isLoading) and ongoing fetching (isFetching) to provide more granular control over loading states in data loader hooks.

[changeset-bot]

🦋 Changeset detected

Latest commit: 3dca27c

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

This PR includes changesets to release 1 package

Name	Type
@scaleway/use-dataloader	Major

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[codecov]

Codecov Report

❌ Patch coverage is 90.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 94.51%. Comparing base (1a67c49) to head (3dca27c).
⚠️ Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
packages/use-dataloader/src/useDataLoader.ts	85.71%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2858      +/-   ##
==========================================
- Coverage   94.66%   94.51%   -0.16%     
==========================================
  Files          33       33              
  Lines         918      929      +11     
  Branches      140      144       +4     
==========================================
+ Hits          869      878       +9     
- Misses         26       28       +2     
  Partials       23       23              

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