Remove performance metrics from cypress (#9467)

They are unfortunately unreliable and have been broken since June anyways.

cypress/e2e/create-room/create-room.spec.ts

@@ -54,12 +54,10 @@ describe("Create Room", () => {
             // Fill room address
             cy.get('[label="Room address"]').type("test-room-1");
             // Submit
-            cy.startMeasuring("from-submit-to-room");
             cy.get(".mx_Dialog_primary").click();
         });
 
         cy.url().should("contain", "/#/room/#test-room-1:localhost");
-        cy.stopMeasuring("from-submit-to-room");
         cy.contains(".mx_RoomHeader_nametext", name);
         cy.contains(".mx_RoomHeader_topic", topic);
     });