[Common] Preserve fatalWhenNull state in PIDTOFParamService

[romainschotter]

• put fatalWhenNull back to its initial value instead of true

@singhra1994 this should fix the crash in your train.

@njacazio for your information

[github-actions]

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

[alibuild]

Error while checking build/O2Physics/o2 for 9c38006 at 2026-07-21 11:55:

No log files found

Full log here.

[alibuild]

Error while checking build/O2Physics/code-check for 9c38006 at 2026-07-21 12:02:

## 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/ad5dcb8204bb6ea0cac6ebdb1026085f13774d87/O2Physics-code-check/errors.txt
Common/Core/PID/PIDTOFParamService.cxx:49:116: error: the const qualified parameter 'task' is copied for each invocation; consider making it a reference [performance-unnecessary-value-param,-warnings-as-errors]
Common/Core/PID/PIDTOFParamService.cxx:73:65: error: the const qualified parameter 'task' is copied for each invocation; consider making it a reference [performance-unnecessary-value-param,-warnings-as-errors]
Common/Core/PID/PIDTOFParamService.cxx:137:5: error: use auto when initializing with a template cast to avoid duplicating the type name [modernize-use-auto,-warnings-as-errors]
Common/Core/PID/PIDTOFParamService.cxx:215:5: error: use auto when initializing with a template cast to avoid duplicating the type name [modernize-use-auto,-warnings-as-errors]
Common/Core/PID/PIDTOFParamService.cxx:288:8: error: destructor of 'TOFSupport' is public and non-virtual [cppcoreguidelines-virtual-class-destructor,-warnings-as-errors]
Common/Core/PID/PIDTOFParamService.cxx:297:29: error: use designated initializer list to initialize 'ServiceHandle' [modernize-use-designated-initializers,-warnings-as-errors]
Common/Core/PID/PIDTOFParamService.cxx:301:22: error: do not use reinterpret_cast [cppcoreguidelines-pro-type-reinterpret-cast,-warnings-as-errors]
++ [[ 0 -gt 0 ]]
++ [[ 7 -gt 0 ]]
++ exit 1
--

Full log here.