fix(exmaples): actix web should use TokioCurrentThread as runtime

[TommyCpp]

small changes to address an issue in examples.

[codecov]

Codecov Report

Merging #734 (a69879f) into main (b695ba1) will decrease coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main     #734      +/-   ##
==========================================
- Coverage   71.50%   71.48%   -0.02%     
==========================================
  Files         102      102              
  Lines        8593     8593              
==========================================
- Hits         6144     6143       -1     
- Misses       2449     2450       +1     

Impacted Files	Coverage Δ
opentelemetry/src/sdk/metrics/controllers/push.rs	80.00% <0.00%> (-3.34%)	⬇️

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[djc]

It would be useful if there was a bit more context in the comments and/or commit message about why this example should use the current thread runtime.

[TommyCpp]

It would be useful if there was a bit more context in the comments and/or commit message about why this example should use the current thread runtime.

Sorry I somehow missed this before merging 😞 . I will add some comments in the example to explain this. But in general actix web is running on tokio single thread scheduler so the runtime has to be TokioCurrentThread