add code coverage (#852)

Add Cypress code coverage using Istanbul nyc

![image](https://github.com/maputnik/editor/assets/60476837/e7c364b7-7b54-4bf1-85aa-ee6fb19cc40c)

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Co-authored-by: shelly_goldblit <shelly_goldblit@dell.com>
Co-authored-by: Harel M <harel.mazor@gmail.com>

cypress.config.ts

@@ -1,10 +1,20 @@
 import { defineConfig } from "cypress";
+import { createRequire } from "module";
+const require = createRequire(import.meta.url);
 
 export default defineConfig({
+  env: {
+    codeCoverage: {
+      exclude: "cypress/**/*.*",
+    },
+  },
   e2e: {
     setupNodeEvents(on, config) {
       // implement node event listeners here
+      require("@cypress/code-coverage/task")(on, config);
+      return config;
     },
+    baseUrl: "http://localhost:8888",
     retries: {
       runMode: 2,
       openMode: 0,