Allow unknown fields when parsing typed events

[ryanchristo]

Summary of Bug

Adding fields in protobuf are intended to be non-breaking API changes / backwards compatible. The current implementation of ParseTypedEvent throws an error when parsing protobuf messages with new fields.

We've encountered this issue with a new field added to a custom module event and with the authz_msg_index field that was added in #12668. The following addition would make ParseTypedEvent backwards compatible:

	unmarshaler := jsonpb.Unmarshaler{AllowUnknownFields: true}

	err = unmarshaler.Unmarshal(strings.NewReader(string(attrBytes)), protoMsg)
	if err != nil {
		return nil, err
	}

Version

main, v0.47, v0.46

Steps to Reproduce

Use ParseTypedEvent with a message executed via MsgExec.

[alexanderbez]

@aaronc this seems reasonable to you right?