feat: feature-flag details page `/featureflags/:id`

[MehulKChaudhari]

Issue Description

Clicking on a feature-flag should open a page /featureflags/:id that includes:

• A toggle to enable or disable the feature-flag.
• A field to select users to grant them access to the feature

Expected Behavior

When clicking on a feature-flag, the user should be directed to the feature-flag’s detail page (/featureflags/:id), where:

• A toggle allows enabling or disabling the feature-flag.
• A user selection field is available to assign specific users access to the feature.

Note: We don't have any mockups/figma for this. Just make the colors etc reference from other RDS sites and match the design system.

Current Behavior

Currently, there is no feature-flag detail page, or the page does not display the toggle or user selection field for granting access to specific users.

Reproducibility

• This issue is reproducible
• This issue is not reproducible

Steps to Reproduce

Severity/Priority

• Critical
• High
• Medium
• Low

Additional Information

Checklist

• I have read and followed the project's code of conduct.
• I have searched for similar issues before creating this one.
• I have provided all the necessary information to understand and reproduce the issue.
• I am willing to contribute to the resolution of this issue.