[Network-controller-upgrade] Remove Feature Flag and Fix E2E Tests

This issue involves removing the feature flag `MM_NETWORK_UI_REDESIGN_ENABLED` that currently gates the UI changes and ensuring that all end-to-end (E2E) tests are updated and passing. The feature flag was initially introduced to control the rollout of the new UI changes. With the feature now stable, it is time to remove the flag and make the changes permanent.

**Tasks:**

**Remove Feature Flag:**
Identify all instances of the feature flag in the codebase.
Remove the feature flag checks and ensure that the new UI changes are always enabled.
Clean up any related code that is no longer necessary.

**Update E2E Tests:**
Review all existing E2E tests to ensure they are compatible with the new UI changes.
Update the tests to remove any dependencies on the feature flag.
Add new E2E tests if necessary to cover any new functionality introduced by the UI changes.

**Run and Fix E2E Tests:**
Run the full suite of E2E tests to identify any failing tests.
Fix any issues identified during the test run to ensure all tests pass.
Ensure that the tests cover all critical user flows and edge cases.