Simplify registering traces sample callback

[maciejwalkowiak]

📜 Description

Simplify registering traces sample callback in Spring integration.

💡 Motivation and Context

Similar to how TracesSamplerCallback is auto-configured in Spring Boot integration, Spring integration should detect if such bean exits and if so, set it on SentryOptions.

💚 How did you test it?

📝 Checklist

• I reviewed submitted code
• I added tests to verify changes
• All tests passing
• No breaking changes

[codecov-io]

Codecov Report

Merging #1184 (d8fe77b) into main (9e98134) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@             Coverage Diff              @@
##               main    #1184      +/-   ##
============================================
+ Coverage     75.31%   75.33%   +0.01%     
  Complexity     1669     1669              
============================================
  Files           173      173              
  Lines          5826     5829       +3     
  Branches        571      571              
============================================
+ Hits           4388     4391       +3     
  Misses         1174     1174              
  Partials        264      264              

Impacted Files	Coverage Δ	Complexity Δ
.../io/sentry/spring/SentryInitBeanPostProcessor.java	93.75% <100.00%> (+1.44%)	5.00 <0.00> (ø)

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[marandaneto]

LGTM
missing changelog, as if a user did it manually, now it's done automatically.