Collect coverage only from unit tests

Because of turbo, unit tests and integration tests can run in
different order.

Before adding turbo, the test script was like "yarn test:unit && yarn
test:integration". If both tests generated coverage, in the coverage
folder there'd factually be the integration test coverage.

But now that they run out of order, we don't know what's in there.

Here I reverted to a state where coverage from unit tests is only
reported, as you normally collect coverage from unit tests.

packages/sdk/package.json

@@ -12,7 +12,7 @@
     "build": "rimraf lib server && rollup -c",
     "test": "yarn test:unit && yarn test:integration",
     "test:unit": "jest ./unit -c ./jest.config.unit.ts --coverage",
-    "test:integration": "jest ./integration -c ./jest.config.integration.ts --runInBand --coverage",
+    "test:integration": "jest ./integration -c ./jest.config.integration.ts --runInBand",
     "lint": "eslint . --ext .ts,.js",
     "prepublish": "yarn build",
     "dev": "rimraf lib server && rollup -c -w"