chore: add loading state

Attaching a loading state to the call that's populating the user's Sites and Projects data, so we can show loading indicators in the mobile app.

src/soilId/soilIdSlice.ts

@@ -89,6 +89,7 @@ export type ProjectSoilSettings = Omit<
 const initialState = {
   soilData: {} as Record<string, SoilData>,
   projectSettings: {} as Record<string, ProjectSoilSettings>,
+  loading: false,
 };
 
 export const sameDepth =
@@ -151,6 +152,14 @@ const soilIdSlice = createSlice({
     builder.addCase(deleteProjectDepthInterval.fulfilled, (state, action) => {
       state.projectSettings[action.meta.arg.projectId] = action.payload;
     });
+
+    builder.addCase(fetchSoilDataForUser.fulfilled, (state, action) => {
+      state.loading = false;
+    });
+
+    builder.addCase(fetchSoilDataForUser.pending, (state, action) => {
+      state.loading = true;
+    });
   },
 });