perf: reduce unnecessary animation controllers

[AmosHuKe]

Description

Reduce unnecessary animation controllers (multiple TiltParallax widgets share the same controller).

Frame Time (UI) on the Windows desktop platform (Profile mode):

Number of widgets (TiltParallax)	Before	After
5000 widgets	max ~63 ms/frame avg ~30 ms/frame	max ~28 ms/frame avg ~16 ms/frame
1000 widgets	max ~9 ms/frame avg ~6 ms/frame	max ~6 ms/frame avg ~3 ms/frame
100 widgets	max ~2 ms/frame avg ~0.8 ms/frame	max ~1 ms/frame avg ~0.6 ms/frame

Checklist

Before you create this PR confirm that it meets all requirements listed below by checking the relevant checkboxes ([x]).

• I open this PR to the main branch.
• I did not modify the CHANGELOG.md nor the package version in pubspec.yaml files.
• All existing and new tests are passing.

Breaking Change

Does your PR require package users to manually update their apps to accommodate your change?

• Yes, this is a breaking change.
• No, this is not a breaking change.