fix: respect files property from karma.config on tns test android --bundle command

Rel to:
NativeScript/nativescript-cli#4477
NativeScript/nativescript-cli#1798

Author: Fatme

unit-testing-config-loader.js

@@ -1,8 +1,7 @@
 const { join, relative } = require("path");
 
 module.exports = function ({ appFullPath, projectRoot, angular, rootPagesRegExp }) {
-    // TODO: Consider to use the files property from karma.conf.js
-    const testFilesRegExp = /tests\/.*\.js/;
+    const testFilesRegExp = getKarmaConfig().files;
     const runnerFullPath = join(projectRoot, "node_modules", "nativescript-unit-test-runner");
     const runnerRelativePath = relative(appFullPath, runnerFullPath);
     let source = `
@@ -30,4 +29,16 @@ module.exports = function ({ appFullPath, projectRoot, angular, rootPagesRegExp
     `;
 
     return source;
+}
+
+function getKarmaConfig() {
+    let result = { files: /tests\/.*\.(js|ts)/ };
+    const pathToKarmaConfig = join(__dirname, "../../karma.conf.js");
+    if (existsSync(pathToKarmaConfig)) {
+        try {
+            require(pathToKarmaConfig)({ set: (options) => result = options });
+        } catch (err) { }
+    }
+
+    return result;
 }