ci/codeql: use filter-sarif to filter meson-private

[evelikov]

There is a severe number of false-positive in code scanning caused by inspecting meson-internal test files like 'build/meson-private/tmpzb46osmq/testfile.c'.

As a workaround, use the 'filter-sarif' action to filter out these results before uploading the SARIF (Static Analysis Results Interchange Format).

This PR was inspired by https://github.com/rauc/rauc/pull/1346 and the example from https://github.com/advanced-security/filter-sarif.

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At a glance this will remove ~35 or around half of the reports \o/

NOTE: there is a "path-ignore" option for the scanner itself, although it seems to be language specific - see their issue 1583

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

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🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[lucasdemarchi]

Applied, thanks