[SYCL][Fusion] Remove kernel fusion stubs

[sommerlukas]

Is your feature request related to a problem? Please describe

The kernel fusion integration into the scheduler was removed to make the scheduler leaner.

Some functions and classes could not be removed entirely, as doing so would constitute an ABI-breaking change. For the time being, they have been replaced with dummy implementations.

In the next ABI-breaking window, those stubs should then be removed entirely.

This includes:

• Multiple entries in DataLessPropKind
• queue::supports_fusion()
• fusion_wrapper[.cpp/.hpp]
• The supports_fusion device aspect

Describe the solution you would like

No response

Describe alternatives you have considered

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Additional context

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