[Common] add a function to get chi2IP in fwdtrackUtilities.h

[dsekihat]

[Common] add a function to get chi2IP in fwdtrackUtilities.h

[github-actions]

O2 linter results: ❌ 5 errors, ⚠️ 3 warnings, 🔕 0 disabled

[alibuild]

Error while checking build/O2Physics/code-check for e10bdb3 at 2026-07-19 12:30:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 7 errors and 0 warnings.'
Found 7 errors and 0 warnings.
++ [[ 7 -gt 0 ]]
++ cat /sw/BUILD/c412e61a8a6f27dbcf47f0221b015780b70e2077/O2Physics-code-check/errors.txt
Common/Core/fwdtrackUtilities.h:36:1: error: nested namespaces can be concatenated [modernize-concat-nested-namespaces,-warnings-as-errors]
Common/Core/fwdtrackUtilities.h:138:96: error: repeated branch body in conditional chain [bugprone-branch-clone,-warnings-as-errors]
Common/Core/fwdtrackUtilities.h:257:12: error: no header providing "std::abs" is directly included [misc-include-cleaner,-warnings-as-errors]
Common/Core/fwdtrackUtilities.h:268:13: error: no header providing "std::isfinite" is directly included [misc-include-cleaner,-warnings-as-errors]
Common/Core/fwdtrackUtilities.h:276:19: error: no header providing "std::cos" is directly included [misc-include-cleaner,-warnings-as-errors]
Common/Core/fwdtrackUtilities.h:277:19: error: no header providing "std::sin" is directly included [misc-include-cleaner,-warnings-as-errors]
Common/Core/fwdtrackUtilities.h:305:15: error: no header providing "std::max" is directly included [misc-include-cleaner,-warnings-as-errors]
++ [[ 0 -gt 0 ]]
++ [[ 7 -gt 0 ]]
++ exit 1
--

Full log here.

[alibuild]

Error while checking build/O2Physics/code-check for 6cbcef7 at 2026-07-19 12:55:

## sw/BUILD/O2Physics-code-check-latest/log
--
========== List of issues found ==========
++ echo 'Found 2 errors and 0 warnings.'
Found 2 errors and 0 warnings.
++ [[ 2 -gt 0 ]]
++ cat /sw/BUILD/aebc082ce6f962f0f0317886aecefe0815bddcae/O2Physics-code-check/errors.txt
Common/Core/fwdtrackUtilities.h:38:1: error: nested namespaces can be concatenated [modernize-concat-nested-namespaces,-warnings-as-errors]
Common/Core/fwdtrackUtilities.h:140:96: error: repeated branch body in conditional chain [bugprone-branch-clone,-warnings-as-errors]
++ [[ 0 -gt 0 ]]
++ [[ 2 -gt 0 ]]
++ exit 1
--

Full log here.

[alibuild]

Auto-approving on behalf of @dsekihat.