Add Developer Custom Metric Tracking to Dashboard

[dhyana6466]

Description

Implemented custom metric tracking for developers on the Home dashboard.
Added a separate section for Custom Metric so developers can add their own metrics in addition to the assigned ones. Since Okta is not implemented yet, I used mock data to simulate this functionality.
Also made sure that metrics are added dynamically and duplicates are not allowed. Existing chart components were reused to keep consistency with the current UI.

Fixes #165

Type of change

• 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 not work as expected)
• This change requires a documentation update

How Has This Been Tested?

Tested locally using the dev server.

Steps:

1. Ran npm run dev
2. Opened the Home dashboard
3. Clicked on "+ Add Metric" in the Custom Metrics section.

Observed that:

• Metrics get added to the chart
• Clicking again adds the next available metric
• No duplicate metrics are added
• Assigned metrics still display correctly

Test Configuration:

• Language Version: JavaScript (React + Vite)
• Webpage (if applicable): http://localhost:5173/

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Screenshot of Output

[hcaballero2]

hi @dhyana6466 we want users to be able to select what metrics they are adding, would you be able to add this feature based on the list of metrics we mention in the tech lead google form? users should be able to select from an alphabetized drop down