stripPrefix filter always add a "/" in path

Describe the bug
stripPrefix filter actually always give "/" while sometime it should be ""

I don't know if this is intended or if it's a bug, in one of my project I had to change the stripPrefix filter in order to call correct URL (without the ending /)

Sample
Add theses tests in BeforeFilterFunctionsTests

The fail with http://localhost/get url, with Strip Prefix to 1 and prefixPath to "/prefix" should call /prefix url, but instead call /prefix/ that is not the same URL

@Test
void stripPrefixAndPrefixPathFail() {
	MockHttpServletRequest servletRequest = MockMvcRequestBuilders
			.get("http://localhost/get").buildRequest(null);

	ServerRequest request = ServerRequest.create(servletRequest,
			Collections.emptyList());

	// StripPrefix 1 should give "" as the path
	ServerRequest modified = BeforeFilterFunctions.stripPrefix(1)
			.andThen(BeforeFilterFunctions.prefixPath("/prefix")).apply(request);

	// PrefixPath should give "/prefix" + "" as the path
	// ACTUALLY gives "/prefix/" as the path, this test FAILS
	assertThat(modified.uri().getRawPath()).isEqualTo("/prefix");
}

@Test
void stripPrefixAndPrefixPathSuccess() {
	MockHttpServletRequest servletRequest = MockMvcRequestBuilders
			.get("http://localhost/get/").buildRequest(null);

	ServerRequest request = ServerRequest.create(servletRequest,
			Collections.emptyList());

	// StripPrefix 1 should give "/" as the path
	ServerRequest modified = BeforeFilterFunctions.stripPrefix(1)
			.andThen(BeforeFilterFunctions.prefixPath("/prefix")).apply(request);

	// PrefixPath should give "/prefix" + "/" as the path
	// This test PASS
	assertThat(modified.uri().getRawPath()).isEqualTo("/prefix/");
}

Start with the proposed cases in BeforeFilterFunctionsTests and trace the stripPrefix and prefixPath entry points. Confirm that stripping /get yields an empty path while stripping /get/ yields "/", then run the relevant gateway tests and ensure both expected paths pass.