Basic search and non-zero-count functionality for callback graph

[jcuypers]

Added the following functionality to the callback graph / debugger:

• Search functionality
• Start of Shortcut codes (s for search pop up, esc to close the search, 0 to toggle non-zero count mode)
• Non-Zero count mode

Contributor Checklist

• [X] I have broken down my PR scope into the following TODO tasks

  • [X] Basic search functionality
  • [X] Filter on non-zero count nodes
  • [X] Dynamic and optimized updates of callbacks and properties while in non-zero counts nodes
  • [ ] Need to sync / limit the search to the actual nodes visible when filtering on non-zero counts

• [X] I have run the tests locally and they passed. (refer to testing section in contributing)

• [ ] I have added tests, or extended existing tests, to cover any new features or bugs fixed in this PR

optionals

• [ ] I have added entry in the CHANGELOG.md
• [ ] If this PR needs a follow-up in dash docs, community thread, I have mentioned the relevant URLS as follows
  • [ ] this GitHub #PR number updates the dash docs
  • [ ] here is the show and tell thread in Plotly Dash community