Log unhealthy executions with warning level

[martintmk]

Confirm the following

• I started this PR by branching from the head of the default branch
• I have targeted the PR to merge into the default branch
• I have included unit tests for the issue/feature
• I have successfully run a local build

[martintmk]

Noticed this while working on samples.

[codecov]

Codecov Report

Merging #1306 (5b6e2a2) into main (833ad99) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##             main    #1306   +/-   ##
=======================================
  Coverage   83.28%   83.28%           
=======================================
  Files         263      264    +1     
  Lines        6299     6301    +2     
  Branches      994      997    +3     
=======================================
+ Hits         5246     5248    +2     
  Misses        844      844           
  Partials      209      209           

Flag	Coverage Δ
macos	83.28% <100.00%> (+<0.01%)	⬆️
windows	83.28% <100.00%> (+<0.01%)	⬆️

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

Impacted Files	Coverage Δ
...xtensions/Telemetry/ResilienceContextExtensions.cs	100.00% <100.00%> (ø)
...xtensions/Telemetry/TelemetryResilienceStrategy.cs	100.00% <100.00%> (ø)

... and 7 files with indirect coverage changes