fix: Filter value resets when switching column types [WEB-1949]

[mapmeld]

Description

In the experiment filter UI, switching from a text filter (Name contains "profile") to a numeric filter (metric = _), calls updateFieldValue(field.id, null);.

Update: the issue is isValid filters fields for the API calls and for saving in updateSettings, so temporary invalid states such as value == null won't be stored, and can get overwritten by previous values. The best option is to separate asJsonString and asSettingsString in the new approach.

2nd Update: now treating this as a race condition, where anything which updates the form field operators and values, is wrapped in an Observable.batch

Test Plan

Set a text query (Name contains "val"); experiments are filtered
Change column name to another text column (Searcher Metric); text value is still used for filter
Change column name to a numeric metric (Searcher Metric Value); value becomes blank
Add new filters; there is no error
Searcher Metric Value filter's value can be set to a number

Checklist

• Changes have been manually QA'd
• User-facing API changes need the "User-facing API Change" label.
• Release notes should be added as a separate file under docs/release-notes/.
  See Release Note for details.
• Licenses should be included for new code which was copied and/or modified from any external code.

[netlify]

✅ Deploy Preview for determined-ui ready!

Name	Link
🔨 Latest commit	a67eea7
🔍 Latest deploy log	https://app.netlify.com/sites/determined-ui/deploys/65b7ca346d5aea000802693f
😎 Deploy Preview	https://deploy-preview-8731--determined-ui.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[codecov]

Codecov Report

Attention: 38 lines in your changes are missing coverage. Please review.

Comparison is base (719169a) 47.42% compared to head (a67eea7) 42.33%.
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8731      +/-   ##
==========================================
- Coverage   47.42%   42.33%   -5.10%     
==========================================
  Files        1047      730     -317     
  Lines      166968   128361   -38607     
  Branches     2242     2242              
==========================================
- Hits        79192    54337   -24855     
+ Misses      87617    73865   -13752     
  Partials      159      159              

Flag	Coverage Δ
harness	?
web	42.50% <2.56%> (-0.01%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
...bui/react/src/pages/F_ExpList/F_ExperimentList.tsx	10.39% <0.00%> (-0.03%)	⬇️
...c/components/FilterForm/components/FilterField.tsx	16.89% <3.57%> (-0.35%)	⬇️

... and 317 files with indirect coverage changes

[ashtonG]

could you investigate why a subsequent call to the form store would be overwritten? if observables can't handle two update calls next to each other, that indicates a larger issue.

[mapmeld]

I've found this doesn't resolve the issue. The formStore's value appears to be reset after fieldValue was set to null.