[VSA] Tidy up chart titles

What does this MR do and why?

Minor clean up for the VSA task by type chart headings and description

• Removes the Type of work heading
• Move tasks by type chart description into a tooltip next to the Tasks by type heading

Screenshots or screen recordings

Before

Before - No data	Before

After

After - no data	After 1 label	After 2+ labels

How to set up and validate locally

Creating a group level value stream

1. Ensure you have an EE license, or stub the cycle_analytics_for_groups license feature to true
2. Create a group
3. Create a project within a group (I recommend creating a project from a template such as the rails template)
4. Create a custom value stream for the new group you created
   Note: The first time you create a value stream in a group, a data aggregation needs to run, in gdk this is usually ~10mins, proceed to make a coffee in the meantime, relax ☕ 😎

Seeding data for the chart

1. Seed some test VSA data

   $ VSA_SEED_PROJECT_ID=<project-id> VSA_ISSUE_COUNT=10 SEED_VSA=true FILTER=cycle_analytics rake db:seed_fu

2. Create some group labels

3. Assign labels to the newly created issues

4. Navigate to the group value stream you created

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #349793 (closed)