fix: remove duplicate method() calls in GHContent class

[BoboTiG]

Description

While reading the code, I saw those duplicate method().

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[codecov]

Codecov Report

Patch coverage: 100.00% and project coverage change: -0.01% ⚠️

Comparison is base (9c00184) 80.10% compared to head (8493eda) 80.10%.

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1697      +/-   ##
============================================
- Coverage     80.10%   80.10%   -0.01%     
  Complexity     2237     2237              
============================================
  Files           215      215              
  Lines          6771     6769       -2     
  Branches        367      367              
============================================
- Hits           5424     5422       -2     
  Misses         1132     1132              
  Partials        215      215              

Files Changed	Coverage Δ
src/main/java/org/kohsuke/github/GHContent.java	75.75% <100.00%> (-0.72%)	⬇️

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