Move type of work vuex code into module

What does this MR do?

As part of #197337 (closed), this MR moves the vuex actions, state, getters and mutations for the tasks by type chart into a separate module.

• Updates the specs for the actions / getters / mutations in the module
• Adds a missing spec for the tasksByTypeChartData getter
• Replaced done callbacks in jest specs with returned promises
• Fixes #214892 (closed)

There will be a follow up MR remove the vuex code for tasks by type from the cycle_analytics/components/base.vue component, and to clean up the remaining tests.

Screenshots

No visual changes

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• Tested in all supported browsers
• Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team

Related to #197337 (closed)