fix: Keep template modal open when invalid

[gt2345]

Ticket

MD-427

Description

When editing/creating a template, if the config is not a valid json, throw an error and keep the modal open.

Test Plan

Create/edit a template with a valid yaml but invalid json config, for example a plain text.
There should be an error thrown, but the modal should keep open.

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.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 43.44%. Comparing base (cdd7a82) to head (20888f0).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #9424      +/-   ##
==========================================
- Coverage   48.61%   43.44%   -5.17%     
==========================================
  Files        1233      909     -324     
  Lines      158972   119049   -39923     
  Branches     2778     2777       -1     
==========================================
- Hits        77278    51718   -25560     
+ Misses      81520    67157   -14363     
  Partials      174      174              

Flag	Coverage Δ
harness	?
web	44.39% <0.00%> (-0.01%)	⬇️

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

Files	Coverage Δ
.../react/src/pages/Templates/TemplateCreateModal.tsx	0.00% <0.00%> (ø)

... and 324 files with indirect coverage changes

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