Setup auto validation of java examples

[mukundansundar]

Description

Added auto validation based on manual trigger for now.

Current Actors example code is not deterministic enough for auto validation.
Also tracing is also not deterministic for validation.

Example successful validation build: https://github.com/mukundansundar/java-sdk/runs/1796635852?check_suite_focus=true

Issue reference

We strive to have all PR being opened based on an issue, where the problem or feature have been discussed prior to implementation.

Please reference the issue this PR will close: #[issue number]

Checklist

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• Code compiles correctly
• Created/updated tests
• Extended the documentation

[wcs1only]

Love it!

[codecov]

Codecov Report

Merging #464 (6682e71) into master (ba49606) will decrease coverage by 0.13%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master     #464      +/-   ##
============================================
- Coverage     80.25%   80.12%   -0.14%     
+ Complexity      982      981       -1     
============================================
  Files            89       89              
  Lines          3049     3049              
  Branches        328      328              
============================================
- Hits           2447     2443       -4     
- Misses          440      443       +3     
- Partials        162      163       +1     

Impacted Files	Coverage Δ	Complexity Δ
sdk/src/main/java/io/dapr/utils/Retry.java	50.00% <0.00%> (-25.00%)	1.00% <0.00%> (-1.00%)

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