fix: Report and retry media failures for every camera in a grid (#2658)

- Closes: #2637
 - Related: #2099

src/scss/media-grid.scss

@@ -37,12 +37,18 @@
   // not change in size (even border-box sizing appears to allow size to change
   // when the element has a non-fixed height).
   border: var(--advanced-camera-card-grid-border-size) solid transparent;
+
+  // Unselected cells cannot be usefully scrolled, so ensure notifications do
+  // not show scrollbars.
+  --advanced-camera-card-notification-block-overflow-y: hidden;
 }
 
 ::slotted([selected]) {
   border: var(--advanced-camera-card-grid-border-size) solid
     var(--advanced-camera-card-grid-selected-border-color);
 
+  --advanced-camera-card-notification-block-overflow-y: auto;
+
   // Selected width = columns × selection factor, capped at 100%.
   width: min(
     100%,

src/scss/notification-block.scss

@@ -29,7 +29,9 @@
   padding: 24px;
   max-width: min(92%, 500px);
   max-height: 100%;
-  overflow-y: auto;
+
+  // A container that cannot usefully be scrolled can set this to 'hidden'.
+  overflow-y: var(--advanced-camera-card-notification-block-overflow-y, auto);
   scrollbar-width: thin;
   text-align: center;
 }