task: inline the venv activate and the command

The following syntax for the `cmds` fields doesn't work as expected and the
first line triggers a failure. The venv envvars are never properly initialized.

```
- >
  source "${VIRTUAL_ENV}/bin/activate" &&
  yarn run test-e2e
```

Taskfile.yml

@@ -149,27 +149,21 @@ tasks:
     deps:
       - package
     cmds:
-      - >
-        source "${VIRTUAL_ENV}/bin/activate" &&
-        yarn run test-e2e
+      - source "${VIRTUAL_ENV}/bin/activate" && yarn run test-e2e
     interactive: true
   test-ui:
     desc: Run UI tests
     deps:
       - package
     cmds:
-      - >
-        source "${VIRTUAL_ENV}/bin/activate" &&
-        yarn run test-ui-current
+      - source "${VIRTUAL_ENV}/bin/activate" && yarn run test-ui-current
     interactive: true
   test-ui-old:
     desc: Run UI tests (oldest vscode)
     deps:
       - package
     cmds:
-      - >
-        source "${VIRTUAL_ENV}/bin/activate" &&
-        yarn run test-ui-oldest
+      - source "${VIRTUAL_ENV}/bin/activate" && yarn run test-ui-oldest
     interactive: true
   package:
     vars: