fix: Exclude endowments barrel from coverage

The endowments.ts barrel file is a pure re-export module with no
logic to test, matching the existing exclusion pattern for index.ts.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: sirtimid

packages/snaps-execution-environments/jest.config.js

@@ -10,6 +10,7 @@ module.exports = deepmerge(baseConfig, {
   coverageReporters: ['html', 'json-summary', 'json'],
   coveragePathIgnorePatterns: [
     './src/index.ts',
+    './src/endowments.ts',
     './src/iframe/index.ts',
     './src/offscreen/index.ts',
     './src/webworker/executor/index.ts',