Mess around with proto files in a probably doomed attempt to resolve relayer issues

[hdevalence]

When running the relayer, we get an error that

panic: proto: file "cosmos_proto/cosmos.proto" is already registered
	previously from: "github.com/cosmos/cosmos-proto"
	currently from:  "buf.build/gen/go/penumbra-zone/ibc-go-vendor/protocolbuffers/go/cosmos_proto"
See https://developers.google.com/protocol-buffers/docs/reference/go/faq#namespace-conflict

This is an entirely self-inflicted issue; there's no actual problem here, other than the totally unreasonable requirement that every .proto file across all source code in the dependency tree has a unique filename.

To paraphrase Werner Herzog,

It's like a curse weighing on an entire [ecosystem]. And whoever... goes too deep into this has his share of this curse. So we are cursed with what we are doing here. It's a [language] that God, if he exists has - has created in anger.

As we have chosen to use the Go relayer, we have our share of this curse. Let us examine it.

~/c/p/relayer (pprovider-new|✔) $ go mod why -m buf.build/gen/go/penumbra-zone/ibc-go-vendor/protocolbuffers/go
github.com/cosmos/relayer/v2/relayer/chains/penumbra
buf.build/gen/go/penumbra-zone/penumbra/protocolbuffers/go/penumbra/core/ibc/v1alpha1
buf.build/gen/go/penumbra-zone/ibc-go-vendor/protocolbuffers/go/ibc/core/client/v1

suggesting that the IBC package depends on ibc-go-vendor, even though the penumbra module's buf.yaml specifies

deps:
- buf.build/cosmos/ibc

This is weird. In an attempt to figure out what's going on, try removing the
ibc-go-vendor package entirely, to see what's happening.

In the future, we should move all of the Rust imports to use the proto files pulled from Buf, but this requires either (a) telling prost/tonic about where to find the proto files in the Buf module cache or (b) telling Buf how to drive prost and tonic. (a) seems easier but for now, we can just accept a
little bit of divergence.