tests: use the mocha tdd mode everywhere and drop karma-chai

Use tdd in all cases to be more consisstend.
Also since last year we can use chai with rollup directly, so
do that everywhere instead of relying on karma-chai injecting
it in to the global scope.

packages/qr-code-scanner/package.json

@@ -14,8 +14,8 @@
     "eslint-plugin-jsdoc": "^30.7.3",
     "i18next-scanner": "^2.10.2",
     "karma": "^5.1.0",
-    "karma-chai": "^0.1.0",
     "karma-chrome-launcher": "^3.0.0",
+    "karma-firefox-launcher": "^1.3.0",
     "karma-mocha": "^2.0.1",
     "mocha": "^8.0.1",
     "puppeteer": "^5.3.1",

packages/qr-code-scanner/test/unit.js

@@ -5,13 +5,13 @@ import '../src/dbp-qr-code-scanner';
 suite('dbp-qr-code-scanner basics', () => {
   let node;
 
-  suiteSetup(async () => {
+  setup(async () => {
     node = document.createElement('dbp-qr-code-scanner');
     document.body.appendChild(node);
     await node.updateComplete;
   });
 
-  suiteTeardown(() => {
+  teardown(() => {
     node.remove();
   });
 

yarn.lock

@@ -5072,11 +5072,6 @@ jszip@^3.2.2, jszip@^3.5.0:
     readable-stream "~2.3.6"
     set-immediate-shim "~1.0.1"
 
-karma-chai@^0.1.0:
-  version "0.1.0"
-  resolved "https://registry.yarnpkg.com/karma-chai/-/karma-chai-0.1.0.tgz#bee5ad40400517811ae34bb945f762909108b79a"
-  integrity sha1-vuWtQEAFF4Ea40u5RfdikJEIt5o=
-
 karma-chrome-launcher@^3.0.0:
   version "3.1.0"
   resolved "https://registry.yarnpkg.com/karma-chrome-launcher/-/karma-chrome-launcher-3.1.0.tgz#805a586799a4d05f4e54f72a204979f3f3066738"