Update cppcheck to v2.10

[thomashampson]

Cppcheck should be updated so we can benefit from improvements. Needs to be updated on the Jenkins builders and in the conda developer .yml files. Also need to update suppressions list if required.

[thomashampson]

2.6.2, 2.6.3 and 2.7 all have internal cppcheck errors, e.g.:

</error>
<error id="cppcheckError" severity="error" msg="Internal error: Child process crashed with signal 11" verbose="Internal error: Child process crashed with signal 11">
    <location file="/mantid_src/Framework/DataObjects/src/MDBoxSaveable.cpp " line="0" column="0"/>
</error>

[thomashampson]

try 2.7.2

[thomashampson]

2.7.5 fails to work:
#### ThreadExecutor::handleRead error, type was:i

Also, oddly it prints out -- cppcheck version: 2.7.4 near the start.

There are still internal cppcheck errors in thisd version too.

[sf1919]

We need to be on v2.6 or higher to upgrade pygments (e.g. https://github.com/mantidproject/mantid/blob/main/mantid-developer-win.yml#L52). We need to update pygments in order to upgrade Sphinx (#34584)

[thomashampson]

We can try v2.10 now that it's on conda-forge

[thomashampson]

Suggestion from Martyn:
For the cppcheck issue with the test files one option might be to add a custom target that just generates the test files and doesn't compile them. Using add_custom_target (https://cmake.org/cmake/help/latest/command/add_custom_target.html) with DEPENDS and the list of cpp files in https://github.com/mantidproject/mantid/blob/main/buildconfig/CMake/FindCxxTest.cmake#L130 would mean you could make the cppcheck cmake target depend on these targets so it will generate the sources first and then run cppcheck without having to compile the tests too.