Fixes facebook#20712 on unix-like OS (facebook#20751)

Summary:
add `packager.sh` for run-android task for unix like system. This only fix on linux and macOS.
pass all current ci.
none
 [GENERAL] [BUGFIX] [CLI] - add `packager.sh` back for run-android task
Pull Request resolved: facebook#20751

Differential Revision: D9398197

Pulled By: hramos

fbshipit-source-id: 213b066c0c034136c5ad5bbf8d45c6f331b1d185

Author: gengjiawen

package.json

@@ -103,6 +103,7 @@
     "scripts/ios-install-third-party.sh",
     "scripts/launchPackager.bat",
     "scripts/launchPackager.command",
+    "scripts/packager.sh",
     "scripts/react-native-xcode.sh",
     "jest-preset.json",
     "jest",