fix: rtl loading spinner (#147)

Author: emilyjablonski

src/blocks/LoadingState.scss

@@ -1,5 +1,5 @@
 .seeds-loading-state {
-  --loading-state-background-color: var(--seeds-bg-color-surface-primary);
+  --loading-state-background-color: var(--seeds-bg-color-canvas);
   --loading-state-height: var(--seeds-s60);
   --loading-state-spinner-color: var(--seeds-color-secondary);
   --loading-state-spinner-border-width: 8px;
@@ -18,10 +18,10 @@
       display: block;
       width: var(--loading-state-spinner-size);
       height: var(--loading-state-spinner-size);
-      top: calc(50% - calc(var(--loading-state-spinner-size) / 2));
-      left: calc(50% - calc(var(--loading-state-spinner-size) / 2));
+      inset-block-start: calc(50% - calc(var(--loading-state-spinner-size) / 2));
+      inset-inline-start: calc(50% - calc(var(--loading-state-spinner-size) / 2));
       border: var(--loading-state-spinner-border-width) solid var(--loading-state-spinner-color);
-      border-left-color: transparent;
+      border-inline-start-color: transparent;
       border-radius: 50%;
       opacity: 1;
       animation: spinning-rotation 1.25s linear infinite;