Remove start page for check tool

[CharliePatterson]

Context:

• The Check tool was previously a standalone service, but has since been integrated with a number of other things, to create a more unified service.
• However, the end-to-end service journey is still a bit disjointed, and lacks coherence.
• Having multiple start pages throughout the journey doesn't make sense from a UX perspective.

Acceptance criteria:

• As a data provider, when I navigate to the check tool from the 'step-by-step' page, I go straight into the tool rather than via a 'start page'.

[neilfwar]

remove the code