[v2] Use Consistent Network Observer API "Slashiness"

[c-kruse]

Is your feature request related to a problem? Please describe.

The network observer API spec has URIs defined with a trailing slash, and the implementation adds 301 redirects from the "bare" URI to the "slash-y" URI. I.e. /sites 301s to /sites/. We have decided to align the "slashiness" of the API to the skupper console's current convention, dropping the slash to avoid unneeded redirects.

Describe the solution you'd like

• URIs should not end in a trailing slash.
• Accessing resources using a trailing slash will redirect to the desired un-slashed URI.