misc: read all interactive prompts from /dev/tty, drain leftover input on read failure (#16235)

misc/alpine-install.func

@@ -126,7 +126,7 @@ network_check() {
   fi
 
   if [[ $ipv4_connected == false ]]; then
-    read -r -p "No Internet detected, would you like to continue anyway? <y/N> " prompt
+    read -r -p "No Internet detected, would you like to continue anyway? <y/N> " prompt </dev/tty
     if [[ "${prompt,,}" =~ ^(y|yes)$ ]]; then
       echo -e "${INFO}${RD}Expect Issues Without Internet${CL}"
     else