Don't use strict mode on gulp ts files

Fixes #61000

build/jsconfig.json

+{
+	"compilerOptions": {
+		"module": "commonjs",
+		"target": "es2017",
+		"jsx": "preserve"
+	},
+	"include": [
+		"**/*.js"
+	],
+	"exclude": [
+		"node_modules",
+		"**/node_modules/*"
+	]
+}
\ No newline at end of file

build/tsconfig.json

@@ -16,6 +16,9 @@
 		"noUnusedLocals": true,
 		"noUnusedParameters": true
 	},
+	"include": [
+		"**/*.ts"
+	],
 	"exclude": [
 		"node_modules/**"
 	]