Fix typo error in flatpak script (#12978)

Fix https://github.com/zed-industries/zed/issues/12977

Release Notes:

- N/A

script/flatpak/bundle-flatpak

@@ -11,7 +11,7 @@ channel=$(<crates/zed/RELEASE_CHANNEL)
 
 export CHANNEL="$channel"
 export ARCHIVE="$archive"
-export APP_CLI = "zed"
+export APP_CLI="zed"
 if [[ "$channel" == "dev" ]]; then
     export APP_ID="dev.zed.Zed-Dev"
     export APP_NAME="Zed Devel"