fix(metrics): add files field to exclude src from published npm package

The published npm package included src/ and tsconfig.json (monorepo
leftovers). When consumers' TypeScript resolved to the raw .ts source
files instead of compiled .d.ts declarations, skipLibCheck did not
apply, causing TS2307 errors for devDependency imports like
@webex/event-dictionary-ts.

Adding "files": ["dist"] ensures only compiled output is published,
so consumers always resolve to .d.ts files where skipLibCheck works.

Author: Christina Mullen

packages/@webex/internal-plugin-metrics/package.json

@@ -5,6 +5,9 @@
   "main": "dist/index.js",
   "devMain": "src/index.js",
   "types": "dist/types/index.d.ts",
+  "files": [
+    "dist"
+  ],
   "repository": {
     "type": "git",
     "url": "https://github.com/webex/webex-js-sdk.git",

packages/@webex/plugin-meetings/package.json

@@ -13,6 +13,9 @@
   "main": "dist/index.js",
   "types": "dist/types/index.d.ts",
   "devMain": "src/index.js",
+  "files": [
+    "dist"
+  ],
   "repository": {
     "type": "git",
     "url": "https://github.com/webex/webex-js-sdk.git",