A set of composer fixes (#1187)

* Don't insert a newline on cmd+entrl (close #1173)

* Don't linkify selected text on url-paste (close #1149)

* Disable the adult content controls if there is no media on the post (close #1169)

src/state/models/ui/shell.ts

@@ -102,6 +102,7 @@ export interface RepostModal {
 export interface SelfLabelModal {
   name: 'self-label'
   labels: string[]
+  hasMedia: boolean
   onChange: (labels: string[]) => void
 }