chore(core-flows,inventory,types,medusa): add fixes to inventory module + location levels api (#7629)

what:

- santizes inputs to prevent reserved_quantity from being updated directly
- inventory items create api can create location levels
- add validation to update quantity of reservation items
- general cleanup

RESOLVES CORE-2254

integration-tests/http/__tests__/reservations/admin/reservations.spec.ts

@@ -88,16 +88,25 @@ medusaIntegrationTestRunner({
 
       it("should throw if available quantity is less than reservation quantity", async () => {
         const payload = {
-          quantity: 100000,
+          quantity: 10000,
           inventory_item_id: inventoryItem1.id,
           line_item_id: "line-item-id",
           location_id: stockLocation1.id,
         }
 
         const res = await api
-          .post(`/admin/reservations`, payload, adminHeaders)
+          .post(
+            `/admin/reservations?fields=*inventory_item.location_levels`,
+            payload,
+            adminHeaders
+          )
           .catch((err) => err)
 
+        const res1 = await api.get(
+          `/admin/inventory-items/${inventoryItem1.id}`,
+          adminHeaders
+        )
+
         expect(res.response.status).toBe(400)
         expect(res.response.data).toEqual({
           type: "not_allowed",
@@ -133,8 +142,7 @@ medusaIntegrationTestRunner({
         reservationId = reservationResponse.data.reservation.id
       })
 
-      // TODO: Implement this on the module
-      it.skip("should throw if available quantity is less than reservation quantity", async () => {
+      it("should throw if available quantity is less than reservation quantity", async () => {
         const payload = { quantity: 100000 }
         const res = await api
           .post(`/admin/reservations/${reservationId}`, payload, adminHeaders)