Add bot-message-square (chatbot) icon (#1709)

icons/bot-message-square.json

@@ -0,0 +1,16 @@
+{
+  "$schema": "../icon.schema.json",
+  "contributors": [
+    "danielbayley"
+  ],
+  "tags": [
+    "robot",
+    "ai",
+    "chat",
+    "assistant"
+  ],
+  "categories": [
+    "development",
+    "social"
+  ]
+}

icons/bot-message-square.svg

@@ -0,0 +1,18 @@
+<svg
+  xmlns="http://www.w3.org/2000/svg"
+  width="24"
+  height="24"
+  viewBox="0 0 24 24"
+  fill="none"
+  stroke="currentColor"
+  stroke-width="2"
+  stroke-linecap="round"
+  stroke-linejoin="round"
+>
+  <path d="M12 6V2H8" />
+  <path d="m8 18-4 4V8a2 2 0 0 1 2-2h12a2 2 0 0 1 2 2v8a2 2 0 0 1-2 2Z" />
+  <path d="M2 12h2" />
+  <path d="M9 11v2" />
+  <path d="M15 11v2" />
+  <path d="M20 12h2" />
+</svg>