Upgrade: Drop the redundant safe call on the grace hint

Inside the `!inGrace || …` branch the smart cast already proves
`loadedState.grace` non-null, so the safe call and the `== true`
comparison on the plain Boolean only produced a compiler warning.

Author: d4rken

app/src/gplay/java/eu/darken/amply/upgrade/ui/UpgradeScreen.kt

@@ -157,7 +157,7 @@ private fun UpgradeAcquisitionContent(
 
     // During a YOUNG grace episode the offers box is hidden: likely a blip, and offers next to "still
     // active" would contradict it. An aged episode brings them back.
-    if (!inGrace || loadedState.grace?.showDiagnostics == true) {
+    if (!inGrace || loadedState.grace.showDiagnostics) {
         UpgradeOffersBox(
             uiState = uiState,
             onIap = onIap,