fix(app): fix unhandled undefined selectedLabware when exiting LPC (#18384)

Fixes a whitescreen when exiting LPC on the desktop app from the "labware list" view.

#18300 accounts for some specific gantry movement when exiting on the desktop app, but we should not type assert selectedLabware or offsetLocationDetails here: these can very much be undefined if the user clicks the exit button on the "labware list view". I don't know why I decided we needed to type assert here to begin with, whoops.

Author: mjhuff

app/src/organisms/LabwarePositionCheck/steps/DetachProbe.tsx

@@ -15,10 +15,6 @@ import {
 import { DescriptionContent, TwoColumn } from '/app/molecules/InterventionModal'
 
 import type { LoadedPipette } from '@opentrons/shared-data'
-import type {
-  OffsetLocationDetails,
-  SelectedLwOverview,
-} from '/app/redux/protocol-runs'
 import type { LPCWizardContentProps } from '/app/organisms/LabwarePositionCheck/types'
 
 import detachProbe1 from '/app/assets/videos/pipette-wizard-flows/Pipette_Detach_Probe_1.webm'
@@ -37,20 +33,21 @@ export function DetachProbe(props: LPCWizardContentProps): JSX.Element {
   const currentSubstep = useSelector(selectCurrentSubstep(runId))
   const pipette = useSelector(selectActivePipette(runId)) as LoadedPipette
   const pipetteId = pipette.id
-  const selectedLwInfo = useSelector(
-    selectSelectedLwOverview(runId)
-  ) as SelectedLwOverview
+  const selectedLwInfo = useSelector(selectSelectedLwOverview(runId))
   const mostRecentVectorOffset = useSelector(
     selectSelectedLwWithOffsetDetailsMostRecentVectorOffset(runId)
   )
-  const offsetLocationDetails = selectedLwInfo.offsetLocationDetails as OffsetLocationDetails
+  const offsetLocationDetails = selectedLwInfo?.offsetLocationDetails
 
   const handleGoBack = (): void => {
     void toggleRobotMoving(true)
       .then(() => {
         // On the desktop app, ensure the robot returns to the initial offset position instead of the home position
         // when actively calibrating an offset.
-        if (currentSubstep === 'handle-lw/edit-offset/check-labware') {
+        if (
+          currentSubstep === 'handle-lw/edit-offset/check-labware' &&
+          offsetLocationDetails != null
+        ) {
           return home()
             .then(() =>
               handleMoveToInitialOffsetPosition(