Spike: Investigate level of effort of "Label Added" checks

[erictncabramson]

This is to investigate the level of effort with the different approaches laid out in #376

The different approaches are:

Option 1:

• When using "Label added" as a trigger, replace the text input with a text-search of a dynamic drop down of labels predicted by ML models invoked in prior automation rules.
  • the drop down options don't appear until 3 characters have been typed
  • only display the top 10 dynamic results
  • This is similar to how the "Filter labels by name or taxonomy" field works when searching Labels while configuring an Automation Rule

Option 2

• MVP approach: validate behind the scenes and display warning message when they enter a label that is not in the list of labels predicted by ML models invoked in prior automation rules.
  • message says "This label is not predicted by any models used in your prior rules. Please check the list of labels available by navigating to that Automation Rule."