Added progress bar to toast messages for better UI experience

[dhairyashiil]

Brief Title

Added progress bar to toast messages for better UI experience

Acceptance Criteria fulfillment

• [X] Combine progress bar with toast messages so that the progress bar duration matches the time the toast message stays on the screen.
• [X] Ensure the progress bar is dynamically adapted to both light and dark themes.
• [X] Implement border radius for the progress bar to match the toast message style.
• [X] The color of the progress bar should match the toast message's color palette:
• [X] For light theme, the progress bar will be a darker tone.
• [X] For dark theme, the progress bar will be a lighter tone.

Fixes #902

Video/Screenshots

https://github.com/user-attachments/assets/d6672be5-2416-455b-952d-b972ad48d94d

and

https://github.com/user-attachments/assets/cb57ad60-cf60-4ea3-b8d5-4d909e2d966a

PR Test Details

Note: The PR will be ready for live testing at https://rocketchat.github.io/EmbeddedChat/pulls/pr-903 after approval. Contributors are requested to replace <pr_number> with the actual PR number.

[Spiral-Memory]

Looks like a good addition @dhairyashiil

Can we please have completely round in Curve variants, like was before :

[dhairyashiil]

Hello @Spiral-Memory , so are you suggesting removing the progress bar for Curve variants, or do you want a completely round shape along with the progress bar? Which option—first or second?

[Spiral-Memory]

Completely round with progress bar

[dhairyashiil]

Completely round with progress bar

Working on it...

[dhairyashiil]

Done @Spiral-Memory , please check

https://github.com/user-attachments/assets/46678103-b6e6-459c-8eef-e8b5f9fd6a4a

and

https://github.com/user-attachments/assets/3b08afd2-119e-4d06-ad14-837daa1a5c93

[Spiral-Memory]

What do you think @dhairyashiil Should we go with this ? What motivated you to have this change in EmbeddedChat ?