Apply custom message in login dialog on direct access

[knolleary]

Fixes https://github.com/FlowFuse/node-red/issues/25

This PR removes the username/password fields from the login dialog when the editor is accessed directly. We get support requests asking what credentials to use - however we only support accessing the editor via the device agent proxy.

With NR 4.0.6 (to be released imminently), I've added the ability to insert a custom message/button on the login dialog when in this state. Older versions of NR will show a blank dialog.

Note: spotted the dashbaord typo when I took this screenshot for the PR... it will be fixed momentarily.

[Steve-Mcl]

@knolleary not sure if you noticed test fail following removal of type?

[knolleary]

@Steve-Mcl test fix pushed

[Steve-Mcl]

Tested/working/approved

This is how it looks on Win + Chrome

Aesthetically, I do wish the string didn't wrap on the last word (but at the same time I cant think of a better way to phrase it)

[Steve-Mcl]

Aesthetically, I do wish the string didn't wrap on the last word (but at the same time I cant think of a better way to phrase it)

Perhaps 'Access to the editor is managed via FlowFuse' would be a suitable (shorter, non wrapping) alternative?

[knolleary]

Have updated the message to Access the editor through the FlowFuse platform