fix: Initialize property filter string value to empty string

[jperals]

Description

Ticket: AWSUI-61464
Dry run: 7600116220

How has this been tested?

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• Changes include appropriate documentation updates.
• Changes are backward-compatible if not indicated, see CONTRIBUTING.md.
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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 96.99%. Comparing base (567860d) to head (bb8a6c8).
⚠️ Report is 10 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #4039   +/-   ##
=======================================
  Coverage   96.99%   96.99%           
=======================================
  Files         861      861           
  Lines       25207    25209    +2     
  Branches     9098     9099    +1     
=======================================
+ Hits        24450    24452    +2     
- Misses        710      751   +41     
+ Partials       47        6   -41     

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[pan-kot]

This fixes the issue for string properties, but breaks enum and custom properties, see: #4041

[jperals]

Thanks. Changed the logic based on the expected behavior of those tests (empty array for enum and null for custom properties). Also refactored into one test for each.

I rely on the presence of a form property in order to infer a custom property (see token-editor.tsx below? Is there a better way? Nor the internal operator, which is a string, nor the matchedProperty, which is of type InternalFilteringProperty, have enough information about this, and the PropertyFilterTokenType type returned by property.getTokenType only knows about value or enum.

[pan-kot]

Yes, relying on the form sounds good 👍

[pan-kot]

The matchedProperty is of internal property type. It supports derived properties for better ergonomics, so there is no need to find the form like this. Instead, you can either check for getValueFormRenderer(operator) prop, or even extend the getTokenType() to return "value" | "enum" | "custom".

[jperals]

OK, thanks. Updated to use getValueFormRenderer.