refactor(ui): Refactor entity page loading indicators

[jjoyce0510]

Summary

Few important things:

1. Adding placeholder loaders for entity title, entity context path
2. Removing unnecessary duplicate dropdown loaders on entity profile
3. Remove dropdown loader for lineage, add an in-context loading indicator. Avoid noisy loaders.

Checklist

• The PR conforms to DataHub's Contributing Guideline (particularly Commit Message Format)
• Links to related issues (if applicable)
• Tests for the changes have been added/updated (if applicable)
• Docs related to the changes have been added/updated (if applicable). If a new feature has been added a Usage Guide has been added for the same.
• For any breaking change/potential downtime/deprecation/big changes an entry has been made in Updating DataHub

[chriscollins3456]

awesome