feat: add fallback logic for vmagent sending wrong content type

[sunng87]

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Fixes #3929

What's changed and what's your intention?

Added fallback logic to handle situation when vmagent send wrong content type of data.

Checklist

• I have written the necessary rustdoc comments.
• I have added the necessary unit tests and integration tests.
• This PR requires documentation updates.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 85.19%. Comparing base (a1c51a5) to head (854f08f).
Report is 48 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4009      +/-   ##
==========================================
- Coverage   85.61%   85.19%   -0.43%     
==========================================
  Files         972      980       +8     
  Lines      166840   170117    +3277     
==========================================
+ Hits       142838   144928    +2090     
- Misses      24002    25189    +1187     

[zyy17]

LGTM