[PWGCF] reduce ccdb calls and remove redundant histogram bookings in flowGenericFramework.cxx

[EmilGorm]

No description provided.

[github-actions]

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

[alibuild]

Error while checking build/O2Physics/code-check for ee591c4 at 2026-09-21 17:08:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 1 errors and 1 warnings.'
Found 1 errors and 1 warnings.
++ [[ 1 -gt 0 ]]
++ cat /sw/BUILD/343e835ab2a25ec715aa32317f9a6ddd5aaee5e3/O2Physics-code-check/errors.txt
PWGCF/GenericFramework/Tasks/flowGenericFramework.cxx:1205:64: error: no header providing "std::distance" is directly included [misc-include-cleaner,-warnings-as-errors]
++ [[ 1 -gt 0 ]]
++ cat /sw/BUILD/343e835ab2a25ec715aa32317f9a6ddd5aaee5e3/O2Physics-code-check/warnings.txt
PWGCF/GenericFramework/Tasks/flowGenericFramework.cxx:942:11: warning: use auto when initializing with a cast to avoid duplicating the type name [modernize-use-auto]
++ [[ 1 -gt 0 ]]
++ exit 1
--

Full log here.

[alibuild]

Auto-approving on behalf of @EmilGorm.

[vkucera]

@EmilGorm Please remember to fix errors before merging.