[PWGCF] adjust conditional statement and add brackets

[hernasab]

No description provided.

[github-actions]

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

[alibuild]

Error while checking build/O2Physics/code-check for 4ec9ab4 at 2026-07-13 04:54:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 2 errors and 1 warnings.'
Found 2 errors and 1 warnings.
++ [[ 2 -gt 0 ]]
++ cat /sw/BUILD/dc239c0bf38de1675dcc1d534077f8ce30f9cc46/O2Physics-code-check/errors.txt
PWGCF/Flow/Tasks/flowZdcTask.cxx:55:78: error: macro argument should be enclosed in parentheses [bugprone-macro-parentheses,-warnings-as-errors]
PWGCF/Flow/Tasks/flowZdcTask.cxx:57:8: error: constructor does not initialize these fields: ccdb [cppcoreguidelines-pro-type-member-init,-warnings-as-errors]
++ [[ 1 -gt 0 ]]
++ cat /sw/BUILD/dc239c0bf38de1675dcc1d534077f8ce30f9cc46/O2Physics-code-check/warnings.txt
PWGCF/Flow/Tasks/flowZdcTask.cxx:377:78: warning: statement should be inside braces [readability-braces-around-statements]
++ [[ 2 -gt 0 ]]
++ exit 1
--

Full log here.