refactor: tag color handling in announcement components

[julia-rabello]

What is the purpose of this pull request?

EDU-17952

• Replaced hardcoded tag color logic with a centralized function getTagColorByLocalizedName for better maintainability.
• Updated AnnouncementCard and AnnouncementsDropdown components to utilize the new function for determining tag colors.
• Removed redundant type color mappings from the components, enhancing code clarity.

What problem is this solving?

How should this be manually tested?

Screenshots or example usage

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Requires change to documentation, which has been updated accordingly.

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