[PWGDQ] fixed linter errors

[aferrero2707]

Changes needed to silent the Linter errors in qaMatching.cxx.

[github-actions]

O2 linter results: ❌ 0 errors, ⚠️ 3 warnings, 🔕 0 disabled

[alibuild]

Error while checking build/O2Physics/o2 for e84d5c1 at 2026-04-23 16:09:

## sw/BUILD/O2Physics-latest/log
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGDQ/Tasks/qaMatching.cxx:215:26: error: redeclaration of 'double QaMatching::mBzAtMftCenter'
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGDQ/Tasks/qaMatching.cxx:2035:45: error: 'getMatchType' was not declared in this scope; did you mean 'GetMatchType'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGDQ/Tasks/qaMatching.cxx:2086:45: error: 'GetTrueMatchIndex' was not declared in this scope; did you mean 'getTrueMatchIndex'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGDQ/Tasks/qaMatching.cxx:2087:49: error: 'GetTrueMatchIndex' was not declared in this scope, and no declarations were found by argument-dependent lookup at the point of instantiation
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGDQ/Tasks/qaMatching.cxx:2701:43: error: 'getMatchType' was not declared in this scope; did you mean 'GetMatchType'?
/sw/SOURCES/O2Physics/slc9_x86-64-slc9_x86-64/0/PWGDQ/Tasks/qaMatching.cxx:2553:43: error: 'getMatchType' was not declared in this scope; did you mean 'GetMatchType'?
ninja: build stopped: subcommand failed.

Full log here.