Only show TMS endpoints in the landing page, when the server publishes tiles

[doublebyte1]

Overview

This PR harmonizes the behavior of the TMS endpoints section of the landing page with the sections that regard other Standards (e.g.: STAC, OAP), by showing it only when the server publishes data on that Standard.

Related Issue / discussion

#1916

Additional information

If there are not tiles in the server, it should not show the TMS endpoints.

Dependency policy (RFC2)

• I have ensured that this PR meets RFC2 requirements

Updates to public demo

• I have ensured that breaking changes to the pygeoapi master demo server have been addressed
  • https://github.com/geopython/demo.pygeoapi.io/blob/master/services/pygeoapi_master/local.config.yml

Contributions and licensing

(as per https://github.com/geopython/pygeoapi/blob/master/CONTRIBUTING.md#contributions-and-licensing)

• I'd like to contribute [feature X|bugfix Y|docs|something else] to pygeoapi. I confirm that my contributions to pygeoapi will be compatible with the pygeoapi license guidelines at the time of contribution
• I have already previously agreed to the pygeoapi Contributions and Licensing Guidelines