fix: replace true on important create screens (#6822)

This adds replace: true to navigate on the create feature toggle screen
and create project screen. This will make it so you don't go back to the
form after you have created the resource, replacing the entry in the
history with the new url. We can do this in more places, but some of
them require a bit more thought. For example when creating a user, you
navigate from the admin screen to the user page, and then back to the
same screen. Adding `{ replace: true }` in this context makes it so that
when you press back you end up on the same screen, because it's recorded
twice in history.

Another discussion point: 
* Would you expect the edit screens to also replace the history?

frontend/src/component/feature/CreateFeature/CreateFeature.tsx

@@ -67,7 +67,9 @@ const CreateFeature = () => {
             const payload = getTogglePayload();
             try {
                 await createFeatureToggle(project, payload);
-                navigate(`/projects/${project}/features/${name}`);
+                navigate(`/projects/${project}/features/${name}`, {
+                    replace: true,
+                });
                 setToastData({
                     title: 'Toggle created successfully',
                     text: 'Now you can start using your toggle.',

frontend/src/component/project/Project/CreateProject/CreateProject.tsx

@@ -58,7 +58,7 @@ const CreateProject = () => {
             try {
                 await createProject(payload);
                 refetchUser();
-                navigate(`/projects/${projectId}`);
+                navigate(`/projects/${projectId}`, { replace: true });
                 setToastData({
                     title: 'Project created',
                     text: 'Now you can add toggles to this project',