Update dependency io.getunleash:unleash-client-java to v8.4.0

[renovate]

This PR contains the following updates:

Package	Change	Age	Adoption	Passing	Confidence
io.getunleash:unleash-client-java	8.3.1 -> 8.4.0

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Configuration

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[codecov]

Codecov Report

Merging #405 (89b950e) into main (fa9724c) will decrease coverage by 0.64%.
Report is 1 commits behind head on main.
The diff coverage is n/a.

@@             Coverage Diff              @@
##               main     #405      +/-   ##
============================================
- Coverage     78.06%   77.42%   -0.64%     
+ Complexity      457      454       -3     
============================================
  Files            86       86              
  Lines          1094     1094              
  Branches         72       72              
============================================
- Hits            854      847       -7     
- Misses          204      208       +4     
- Partials         36       39       +3     

see 1 file with indirect coverage changes