ROU-12485: add fontAwesome as fallback

[BenOsodrac]

This pull request updates the icon library handling and styling for dropdown components, standardizing icon usage and improving fallback behavior. The main focus is on switching the default icon library to FontAwesome, updating icon variables, and refining how icons are rendered in dropdowns.

Icon library and variable updates:

• Changed the default icon library from Phosphor to FontAwesome by updating the CSS variable definitions in src/scss/01-foundations/_icon-library-odc.scss. All icon variables now use FontAwesome codes as the fallback, with Phosphor as an alternative.
• Updated the logic in IconLibrary.ts so that if the new icon library is an empty string, no changes are made, preventing unnecessary updates.

Dropdown styling improvements:

• Moved the caret icon styling for dropdown selected values from the component-specific SCSS (_dropdown-serverside.scss) to the foundational icon library SCSS (_icon-library-o11.scss), ensuring consistent icon rendering and font usage.
• Removed direct FontAwesome icon and font styling from the dropdown's SCSS, relying instead on the global icon library variables and styles for consistency.

Checklist

• tested locally
• documented the code
• clean all warnings and errors of eslint
• requires changes in OutSystems (if so, provide a module with changes)
• requires new sample page in OutSystems (if so, provide a module with changes)

[sonarqubecloud]

Quality Gate failed

Failed conditions
C Reliability Rating on New Code (required ≥ A)

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