[rust] Panic if JSON output is used but no entries are collected

[bonigarcia]

Description

This PR includes a panic call when JSON output is used (e.g., by the bindings) but no entries are collected by SM.

Motivation and Context

In theory, this panic will never be called. But if it happens, it will allow to discover that problems like #13091 are caused in the Rust side.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the contributing document.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (aaec17e) 57.70% compared to head (d1d7382) 57.70%.
Report is 2 commits behind head on trunk.

❗ Current head d1d7382 differs from pull request most recent head a62eda7. Consider uploading reports for the commit a62eda7 to get more accurate results

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Additional details and impacted files

@@           Coverage Diff           @@
##            trunk   #13101   +/-   ##
=======================================
  Coverage   57.70%   57.70%           
=======================================
  Files          86       86           
  Lines        5289     5289           
  Branches      208      208           
=======================================
  Hits         3052     3052           
  Misses       2029     2029           
  Partials      208      208           

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