table designer editor icon (#17608)

* icon for table designer

* use more specific name

* use sql defined schema

extensions/theme-seti/icons/vs-seti-icon-theme.json

@@ -1517,6 +1517,9 @@
 		},
 		"scmp_dark": {
 			"iconPath": "./images/scmp_inverse.svg"
+		},
+		"table-designer": {
+			"iconPath": "./images/table.svg"
 		}
 	},
 	"file": "_default",
@@ -1809,6 +1812,7 @@
 		"dashboard": "_shell",
 		"profiler": "_csv",
 		"Schema Compare": "scmp_dark",
+		"table-designer": "table-designer"
 	},
 	"languageIds": {
 		"bat": "_windows",