Use the tag-related Task methods in the Tags column type (#3911)

Use the tag-related Task methods in the Tags column type

This column type was taking a shortcut by assuming the `tags` property
contains a comma-separated list of tags. This property is now deprecated
and tags are stored in individual properties. The tag-related Task
methods correctly access these new properties.

Includes a test for the fixed behavior and a test demonstrating that
`task info` already does the right thing.

.github/workflows/tests.yaml

@@ -7,6 +7,9 @@ jobs:
   coverage:
     runs-on: ubuntu-latest
     steps:
+      - name: Update apt repos
+        run: sudo apt-get update -y
+
       - name: Install apt packages
         run: sudo apt-get install -y build-essential cmake git uuid-dev faketime locales python3 curl gcovr ninja-build