feat: add styling for MessageBlocked component (#327)

### 🎯 Goal

Adds styling for MessageBlocked component.

Ref: GetStream/stream-chat-react#2675

Author: arnautov-anton

src/v2/styles/Message/Message-layout.scss

@@ -120,6 +120,10 @@
     grid-template-areas: 'message';
   }
 
+  &.str-chat__message--blocked {
+    grid-template-areas: 'message';
+  }
+
   &.str-chat__message--system {
     grid-template-areas: 'message';
     grid-template-columns: auto;
@@ -260,6 +264,10 @@
     @include chat-bubble-spacing;
   }
 
+  .str-chat__message--blocked-inner {
+    @include chat-bubble-spacing;
+  }
+
   .str-chat__quoted-message-bubble {
     @include chat-bubble-spacing;
     display: flex;

src/v2/styles/Message/Message-theme.scss

@@ -118,6 +118,30 @@
   /* Box shadow applied to a deleted message */
   --str-chat__deleted-message-box-shadow: none;
 
+  /* The border radius used for the borders of a deleted message */
+  --str-chat__blocked-message-border-radius: var(--str-chat__border-radius-md);
+
+  /* The text/icon of a deleted message */
+  --str-chat__blocked-message-color: var(--str-chat__text-low-emphasis-color);
+
+  /* The background of a deleted message */
+  --str-chat__blocked-message-background-color: var(--str-chat__secondary-surface-color);
+
+  /* Top border of a deleted message */
+  --str-chat__blocked-message-border-block-start: none;
+
+  /* Bottom border of a deleted message */
+  --str-chat__blocked-message-border-block-end: none;
+
+  /* Left (right in RTL layout) border of a deleted message */
+  --str-chat__blocked-message-border-inline-start: none;
+
+  /* Right (left in RTL layout) border of a deleted message */
+  --str-chat__blocked-message-border-inline-end: none;
+
+  /* Box shadow applied to a deleted message */
+  --str-chat__blocked-message-box-shadow: none;
+
   /* The border radius used for the borders of a system message */
   --str-chat__system-message-border-radius: 0;
 
@@ -214,6 +238,11 @@
     font: var(--str-chat__body2-text);
   }
 
+  .str-chat__message--blocked-inner {
+    @include utils.component-layer-overrides('blocked-message');
+    font: var(--str-chat__body2-text);
+  }
+
   &.str-chat__message--me .str-chat__message-bubble {
     color: var(--str-chat__own-message-bubble-color);
     background-color: var(--str-chat__own-message-bubble-background-color);