azure-functions-core-tools.rb to support 4.x version

Since according to [1] Version 4 is the new default. Would it be possible to switch the `azure-functions-core-tools@4.rb` to `azure-functions-core-tools.rb` so it gets rolled out by default?

[1] https://learn.microsoft.com/en-us/azure/azure-functions/functions-run-local?tabs=v4%2Clinux%2Ccsharp%2Cportal%2Cbash

Start by comparing azure-functions-core-tools@4.rb with the requested azure-functions-core-tools.rb naming and read the linked Azure Functions documentation. Done means the 4.x formula is the default formula while the existing versioned formula is handled consistently.

Written by the indexing model from the issue text.