Hotfix/Fix test_package error.

[PengZheng]

As observed, trying to scheduling event to an inactive framework will lead to test_package failure:

celix/3.0.0 (test package): RUN: ./use_components_ready_check

Hello world from C bundle with id 2
Bundle 1: apache_celix_components_ready_check
Bundle 2: hello
Goodbye world from C bundle with id 2
[2024-06-24T09:03:00] [   info] [celix_framework] [framework_start:483] Celix framework started

ERROR: celix/3.0.0 (test package): Error in test() method, line 149
	self.run("./use_components_ready_check",
	ConanException: Error 1 while executing

This PR fixes this by only issuing a warning instead of returning error.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 90.27%. Comparing base (39e2282) to head (f82223d).
Report is 12 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #757   +/-   ##
=======================================
  Coverage   90.26%   90.27%           
=======================================
  Files         226      226           
  Lines       26319    26320    +1     
=======================================
+ Hits        23758    23760    +2     
+ Misses       2561     2560    -1     

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