Remove c8 coverage reporter (#7006)

vitest.config.ts

@@ -4,6 +4,10 @@ import {defineConfig} from 'vitest/config';
 // eslint-disable-next-line import/no-default-export
 export default defineConfig({
     test: {
+        coverage: {
+            provider: 'v8',
+            reporter: ['text', 'json', 'html'],
+        },
         include: ['test/**/*.ts'],
         exclude: ['test/_*.ts', 'test/utils.ts'],
         setupFiles: ['/test/_setup-fake-aws.ts', '/test/_setup-log.ts'],