[OGUI-689] Tree refresh should keep state of opened objects

[hehoon]

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• branch and/or PR name(s) includes JIRA ID
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Changes:

• The tree on the object tree page now persists its expanded node state in local storage.

Note:

• The estimated storage size (in bytes) is approximately: A * (N + 7) * 2
  • A is the number of expanded (opened) nodes
  • N is the average character length of expanded (opened) node names
• The storing of tree node states will break if two identical names are stored directly under the same parent. This limitation already existed in the previous implementation and is unchanged by the current persistence mechanism.
• A temporary workaround was added to handle local storage resets in tests, since some tests are not fully isolated and depend on shared state. Ideally, all tests should be isolated, with local storage and page state fully reset between each test.