fix: dialog flashing in top-left corner before centering

[mateussp97]

Description

This PR fixes a visual bug where the Dialog component briefly flashes in the top-left corner before animating to its centered position. The issue is visible on the documentation site at https://www.tremor.so/docs/ui/dialog.

The root cause was that the dialogContentShow animation keyframes included positioning transforms translate(-50%, -50%) which conflicted with the Tailwind positioning classes already applied to the component (-translate-x-1/2 -translate-y-1/2). This caused a brief render frame where transforms were not correctly applied.

The fix removes the positioning transforms from the animation, letting Tailwind handle the centering while the animation only handles opacity and scale effects.

Related issue(s)

Related to #152 - This fix addresses dialog positioning issues

What kind of change does this PR introduce? (check at least one)

• Bug fix (non-breaking change which fixes an issue)
• New Feature (non-breaking change which adds functionality)
• New Feature (BREAKING CHANGE which adds functionality)
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change? (check one)

• Yes
• No

How has this been tested?

• Tested locally by running the development server and verifying all Dialog examples work correctly
• Verified the animation no longer causes position flash
• Tested with CPU throttling (4x slowdown) in Chrome DevTools to ensure smooth animation even on slower devices
• Confirmed Dialog still animates with fade and scale effects as intended

Screenshots (if appropriate):

Before: Dialog flashes in top-left corner before centering
After: Dialog animates smoothly from center position with only opacity/scale changes

The PR fulfils these requirements:

• It's submitted to the main branch
• Add refs [Bug]: Dialog position issue in Tremor Example page #152 to the related issue section
• My change requires a change to the documentation. (Managed by Tremor Team)
• I have added tests to cover my changes
• Check the "Allow edits from maintainers" option while creating your PR.
• By contributing to Tremor, you confirm that you have read and agreed to Tremor's CONTRIBUTING.md guideline. You also agree that your contributions will be licensed under the Apache License 2.0 license.