Filter out sites from sharing permissions features by using visible flag

[alex-yau-ttd]

• Create a new method getVisibleSiteList in adminServiceClient.ts to call getSiteList() then filter out the appropriate sites before returning to the front end.
• The method of filtering allows for existing sites that have visible==null to still be included, as that is the default for sites that were created before the visible flag was introduced. The default for new sites is visible==true
• Use getVisibleSiteList in the base (/) router and /available in the sites router. These routes are only used for non-admin functionality and does not break core functionality of the website when the current participant has a site that has visible set to false
• Ultimately this hides invisible sites from being included on the sharing permissions count on the home screen, as well as being hidden from the sharing permissions screen (i.e. in the bulk add control, the search and add control, and the sharing permissions table)

Manual testing

Given the following sites exist:

  {
    "name": "a visible site",
    "clientTypes": [
      "DSP"
    ],
    "visible": true, //or null
    ...
  },
  {
    "name": "an invisible site",
    "clientTypes": [
      "DSP"
    ],
    "visible": false,
    ...
  }

We see that a visible site shows up in areas of the UI relating to sharing, but an invisible site does not.

The an invisible site should still show up in admin areas such as approving participant requests.

Other manual testing verified that the functionality of the portal did not break when the user was associated with a site that had visible==false

[alex-yau-ttd]

Sites with visible==false should still show in the participant approval form

[alex-yau-ttd]

It doesn't matter what value visible is in the participant request form, so I just did one with true and one with false