_juce_get_module_definitions filter excludes entries with escaped semicolons

[danra]

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Before this tweak, a juce plugin target which had a target_compile_definitions entry with an escaped semicolon \; would end up generating format-specific targets which not only had a preprocessor definition matching the entry, but also extraneous definitions of the escaped-semicolon-split parts of that entry. For example, an entry of "MY_MACRO=f()\;g();" would end up with the extraneous preprocessor definitions MY_MACRO=f() and g(), in addition to the desired MY_MACRO=f();g();

This is because of how CMake handles escaped semicolons in lists, see e.g. https://gitlab.kitware.com/cmake/cmake/-/issues/20317