Insecure credentials implementation broken on @grpc/grpc-js v1.13.1

[tstirrat15]

Description

This was reported by a user on discord: https://discord.com/channels/844600078504951838/844600078948630559/1352659081139060866

We currently copy in an implementation to work around the grpc-js package preventing you from using bearer token credentials in an insecure context.

This differs from the current implementation, though a git blame shows that the changes to this class happened a long time ago.

My best guess is that something changed in the v1.13.0 release, but I'm having trouble figuring out what that would be.

I'll pin the package in the resolutions in the meantime, and work on a more permanent fix after that.

[tstirrat15]

Could also be related to https://github.com/grpc/grpc-node/releases/tag/%40grpc%2Fgrpc-js%401.13.1, since that lines up with the reports from users.

[tstirrat15]

This is the PR that broke things for us:

https://github.com/grpc/grpc-node/pull/2866/files#diff-7c43d37a239cc91464d8ba94c2ece274bdf5146da1442603b7dc9fdd9b4f8483

I'm hoping this isn't a terrible fix.

[kartikaysaxena]

It seems like the constructor and exposed callCredentials for ChannelCredentials class are removed which is causing this, made a small fix for that.

[tstirrat15]

This should be addressed in #212.