refactor(nms): Remove legacy dashboard

[thmsschmitt]

Summary

The legacy UI that you get if you disable the V2 LTE Dashboard feature flag has be removed to reduce code complexity.

The feature flag itself will be removed later together with the other unused flags.

Test Plan

Make sure that the UI looks as expected for LTE, FEG and FEG_LTE both with V2 LTE Dashboard enabled and disabled.

Use the linter to make sure the all imports can be resolved:

$ yarn eslint .
✖ 186 problems (0 errors, 186 warnings)

✨  Done in 19.35s.

[github-actions]

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[github-actions]

feg-workflow

    2 files  202 suites   38s ⏱️
371 tests 371 ✔️ 0 💤 0 ❌
385 runs  385 ✔️ 0 💤 0 ❌

Results for commit 410512d.

♻️ This comment has been updated with latest results.

[github-actions]

nms-workflow

0 files  0 suites   0s ⏱️
0 tests 0 ✔️ 0 💤 0 ❌

Results for commit 410512d.

♻️ This comment has been updated with latest results.

[github-actions]

cloud-workflow

    7 files  356 suites   2m 36s ⏱️
974 tests 974 ✔️ 0 💤 0 ❌

Results for commit 410512d.

♻️ This comment has been updated with latest results.

[github-actions]

agw-workflow

     77 files     122 suites   7m 30s ⏱️
1 159 tests 1 150 ✔️ 9 💤 0 ❌
1 160 runs  1 151 ✔️ 9 💤 0 ❌

Results for commit 410512d.

♻️ This comment has been updated with latest results.

[thmsschmitt]

@ShubhamTatvamasi @hcgatewood @arunuke would be good to get this reviewed, it is blocking a few things and the infra changes are really minimal.

[ShubhamTatvamasi]

Hi @thmsschmitt, we have to update helm chart versions for NMS and Orc8r both in this.

[ShubhamTatvamasi]

@thmsschmitt, there are other PRs also that will conflict with this PR if we update the helm version, so we will update it at the time of release.