SMART App redirect_uri does not match specification

[LandonTroyReilly]

Describe the bug
The SMART Forms integration specification defines the redirect URI as:

https://healthchecks.smartforms.io/

However, the SMART app sends the redirect URI without the trailing slash:

https://healthchecks.smartforms.io

This causes a redirect URI mismatch when performing strict URI validation.

To Reproduce

1. Launch the SMART Health Checks application.
2. Inspect the SMART authorization request.
3. Observe the redirect_uri value sent by the application.
4. Compare it with the redirect URI defined in the SMART Forms integration specification.

Expected behavior
The SMART app should send the redirect URI exactly as defined in the specification:

https://healthchecks.smartforms.io/