Remove deprecated VelocityTracker constructor - #98541

This removes the default constructor from

• VelocityTracker

This deprecated property has reached end of life after the release of Flutter 2.10

• The replacement is VelocityTracker.withKind.
• ✅ This migration is supported by the dart fix tool.
• 🕐 This API was deprecated in Deprecate VelocityTracker default constructor and added VelocityTracker.withKind constructor #66043, first tagged v1.22

Part of #98537
For the full list of deprecations being removed in this batch, see flutter.dev/go/deprecations-removed-after-2-10

Pre-launch Checklist

• I read the Contributor Guide and followed the process outlined there for submitting PRs.
• I read the Tree Hygiene wiki page, which explains my responsibilities.
• I read and followed the Flutter Style Guide, including Features we expect every widget to implement.
• I signed the CLA.
• I listed at least one issue that this PR fixes in the description above.
• I updated/added relevant documentation (doc comments with ///).
• I added new tests to check the change I am making, or this PR is test-exempt.
• All existing and new tests are passing.

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