Some __kernel_name_generator usages doesn't depends from _ExecutionPolicy type

[SergeyKopienko]

Describe the Bug:
Some __kernel_name_generator usages doesn't includes _ExecutionPolicy type,
but the code where it's implemented contains _ExecutionPolicy inside template params.
This situation allows to write the code with the different _ExecutionPolicy types but to have the same KernelName inside - it's will generate an error in unnamed lambdas switched off.

To Reproduce:
No reproducers.

Expected Behavior:
Probably every __kernel_name_generator should depends on _ExecutionPolicy type if it is used for code specialization.

Additional Context:
Add any other context about the problem here.

Examples where _ExecutionPolicy type is not used in __kernel_name_generator :

oneDPL/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl.h

Line 242 in 84da6ac

using _LocalScanKernel = oneapi::dpl::__par_backend_hetero::__internal::__kernel_name_generator<

oneDPL/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl.h

Line 244 in 84da6ac

using _GroupScanKernel = oneapi::dpl::__par_backend_hetero::__internal::__kernel_name_generator<

oneDPL/include/oneapi/dpl/pstl/hetero/dpcpp/parallel_backend_sycl_reduce.h

Line 321 in 84da6ac

using _ReduceKernel = oneapi::dpl::__par_backend_hetero::__internal::__kernel_name_generator<

[SergeyKopienko]

During implementation of #2093 with fix for this issue we found another option: to use __kernel_name_generator without _ExecutionPolicy but also changing the type of _ExecutionPolicy param in submitters (and one level up functions - in submitter callers) from _ExecutionPolicy&& to const _ExecutionPolicy&.
This approach will give us only one specialization for every execution policy.

[SergeyKopienko]

@rarutyun could you please comment this issue? Is it really an error?