Revert "[Executorch][Quantization][BE] Refactor Choose Qparams (#92592)"
This reverts commit 59071ab1e71891d480ab77af0d619bc5e01094c2.
It breaks `quantization.jit.test_ondevice_quantization.TestOnDeviceDynamicPTQFinalize`, which is not run in OSS, but is mandatory for internal CI.
