[LinalgExt] Drop the unit dims on scatter ops 2/3 #33163

Job	Run time
setup / setup	9s
runtime :: ubuntu-24.04	1m 19s
runtime :: windows-2022	3m 26s
runtime_small	2m 15s
runtime :: macos-14	1m 24s
runtime_tracing :: tracy provider	2m 17s
runtime_tracing :: console provider	1m 0s
linux_x64_bazel / linux_x64_bazel	29m 53s
linux_x64_clang_asan / linux_x64_clang_asan	22m 54s
linux_x64_clang / linux_x64_clang	21m 46s
ci_summary / summary	2s
	1h 26m 25s

Provide feedback