test(procmgr): add spawn-profile Windows E2E with LocalSystem supervisor

Assert dd-procmgr-service runs as LocalSystem and agent-profile children
run as the agent user with a loaded user profile. Requires the MSI installer
to register dd-procmgr-service as LocalSystem (ServiceCustomAction in this PR).

Author: jose-manuel-almaza

test/new-e2e/tests/agent-runtimes/procmgr/procmgr_win_test.go

@@ -185,8 +185,6 @@ func (s *procmgrWindowsSuite) TestAgentProfileDescribeUserMatchesRuntimeUser() {
 		assert.NotEmpty(ct, runtimeUser)
 		assert.Equal(ct, user, runtimeUser,
 			"describe User should match Runtime User for agent-profile children")
-		// MSI stores the machine name as installedDomain for local ddagentuser;
-		// procmgr display normalizes local SAM accounts to .\user.
 		assert.Equal(ct, `.\`+agentUser, user,
 			"local agent user should use registry-style .\\user display")
 	}, 60*time.Second, 2*time.Second)