Update dependency flutter_riverpod to v3

[renovate]

This PR contains the following updates:

Package	Type	Update	Change
flutter_riverpod (source)	dependencies	major	^2.6.1 → 3.3.1

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Warning

Some dependencies could not be looked up. Check the Dependency Dashboard for more information.

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Release Notes

rrousselGit/riverpod (flutter_riverpod)

v3.3.1

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v3.3.0

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v3.2.1

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v3.2.0

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v3.1.0

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v3.0.3

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v3.0.2

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v3.0.1

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v3.0.0

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Configuration

📅 Schedule: Branch creation - At any time (no schedule defined), Automerge - At any time (no schedule defined).

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

♻ Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.

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• If you want to rebase/retry this PR, check this box

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[renovate]

⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

• any of the package files in this branch needs updating, or
• the branch becomes conflicted, or
• you click the rebase/retry checkbox if found above, or
• you rename this PR's title to start with "rebase!" to trigger it manually

The artifact failure details are included below:

File name: frontend/pubspec.lock

Command failed: flutter pub upgrade flutter_riverpod
Because flutter_riverpod >=3.2.1 depends on riverpod 3.2.1 and riverpod_lint 2.6.5 depends on riverpod 2.6.1, flutter_riverpod >=3.2.1 is incompatible with riverpod_lint 2.6.5.
And because no versions of riverpod_lint match >2.6.5 <3.0.0, flutter_riverpod >=3.2.1 is incompatible with riverpod_lint ^2.6.5.
So, because testcase_dashboard depends on both flutter_riverpod 3.3.1 and riverpod_lint ^2.6.5, version solving failed.
Failed to update packages.