use types.MetadataFromVersion in 29-fee callback handlers

[damiannolan]

Pre-requisite:

• imp: adding MetadataFromVersion to 29-fee pkg types #4100

Summary

Fee middleware Metadata can be parsed from the channel version string using a new helper:

metadata, err := types.MetadataFromVersion(version)
if err != nil {
  // handle err
}

We can make use of this in app callbacks within 29-fee such as ChanOpenInit, ChanOpenTry etc..
Essentially replacing the usage of:

var metadata types.Metadata
if err := types.ModuleCdc.UnmarshalJSON([]byte(version), metadata); err != nil {
  // handle err
}

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[stackman27]

@crodriguezvega can i be assigned to this

[crodriguezvega]

Yes, absolutely. Thank you, @stackman27!

[stackman27]

Also would appreciate any other good first issues to work on. Anything that helps me understand different parts of ibc better :))

[crodriguezvega]

Also would appreciate any other good first issues to work on. Anything that helps me understand different parts of ibc better :))

Sure thing. We'll find you some nice ones. :)