Revert URL encoding or check if the URL is already encoded.

[jleach]

I think the issue I fixed in #1479 which was to protect agains spaces or other forbidden characters in tailsLocation has an edge case that is just as problematic. The fn encodeURI will re-encode a URI if it fines a % in it already. This can result in erroneous results and may be more problematic. To fix we can either remove the call to encodeURI added in #1479 or do a quick check to make sure its not already encoded:

Here is an example of the problem. Every time encodeURL is run the query string gets the % re-encoded as %25:

> const url = 'http://foo.example.com?name=Jason Leach'
undefined
> encodeURI(url)
'http://foo.example.com?name=Jason%20Leach'
> encodeURI(encodeURI(url))
'http://foo.example.com?name=Jason%2520Leach'
> encodeURI(encodeURI(encodeURI(url)))
'http://foo.example.com?name=Jason%252520Leach'
> url === decodeURI(encodeURI(url))
true

I can add a quick check like this:

isEncoded = (uri: string) => {
  const aUri = uri ?? ''
  return aUri !== decodeURI(aUri)
}

Results in:

> const isEncoded = (uri) => {
... const aUri = uri ?? ''
... return aUri !== decodeURI(aUri)
... }
undefined
> isEncoded(encodeURI(url))
true
> isEncoded(decodeURI(encodeURI(url)))
false
>