Fix postinstall issues

### FIXED
- When manually installing package globally, `postinstall` script would run without `devDependencies` properly installed.

Author: mrjackyliang

package.json

@@ -1,7 +1,7 @@
 {
   "name": "homebridge-adt-pulse",
   "displayName": "Homebridge ADT Pulse",
-  "version": "3.4.12",
+  "version": "3.4.13",
   "description": "Homebridge security system platform for ADT Pulse",
   "main": "./build/index.js",
   "exports": "./build/index.js",

postinstall.js

@@ -1,6 +1,9 @@
 import { execSync } from 'node:child_process';
 
-if (process.env.npm_config_omit !== 'dev') {
+const isGlobal = process.env.npm_config_global === 'true';
+const isDevOmitted = process.env.npm_config_omit === 'dev';
+
+if (!isGlobal && !isDevOmitted) {
   console.info('Running post-install commands ...');
 
   execSync('npm run build', {