Remove old feature flags - TEMPLATE_SERVICE_PROVIDERS_ENABLED and PROVIDER_STRATEGIES_ENABLED

[MackHalliday]

User Story - Business Need

• Ticket is understood, and QA has been contacted (if the ticket has a QA label).

There were old feature flags identified when working on #1711. While reviewing which task definitions to be removed, it was observed that several task definitions were old feature flags that were all set to True or never turned on. These feature flags with their related task definitions, code paths, and tests should be removed. This user story focused specifically on TEMPLATE_SERVICE_PROVIDERS_ENABLED and PROVIDER_STRATEGIES_ENABLED.

TEMPLATE_SERVICE_PROVIDERS_ENABLED and PROVIDER_STRATEGIES_ENABLED feature flags appear in if statements in the client_to_use method. Both have been set to True in all ENVs for at least 3 years.

Since the method returns a client if the feature flag PROVIDER_STRATEGIES_ENABLED is True, the rest of the method is NOT used.

We need to remove the feature flags TEMPLATE_SERVICE_PROVIDERS_ENABLED and PROVIDER_STRATEGIES_ENABLED. And remove any unused logic and related tests.

User Story(ies)

As a VA Notify Developer,
I want remove old feature flags PROVIDER_STRATEGIES_ENABLED and TEMPLATE_SERVICE_PROVIDERS_ENABLED with related code paths, and task definitions
So that the code runs efficiently and continues to be maintainable.

Additional Info and Resources

See spreadsheet created for ticket #1711 - filter by 'feature flag removal' under the 'removal status' column.

Acceptance Criteria

• TEMPLATE_SERVICE_PROVIDERS_ENABLED and PROVIDER_STRATEGIES_ENABLED feature flags with related task definitions, code paths, and tests are removed
• Unused logic in client_to_use is removed and test updated appropriately
• Test suite and regression test run without fail (Changes should be covered by regression)
• Sending an sms to a provider works as expected (Note: Deliver sms celery task. client_to_use is apart of this code path)
• Sending an email to a provide works as expected (Note: Deliver email celery task. client_to_use is apart of this code path)
• This work is added to the sprint review slide deck (key win bullet point and demo slide)

QA Considerations

• Sending an sms to a provider works as expected (Note: Deliver sms celery task. client_to_use is apart of this code path)
• Sending an email to a provide works as expected (Note: Deliver email celery task. client_to_use is apart of this code path)

Potential Dependencies

[npmartin-oddball]

Hey team! Please add your planning poker estimate with Zenhub @cris-oddball @EvanParish @k-macmillan @MackHalliday @mchlwellman