[Documentation]: Improve gRPC Command Examples for Clarity

[l0g2]

Documentation.

I would like to propose some improvements to the documentation found in the eigenda/inabox README regarding the gRPC commands for sending and retrieving blob status.

Suggested Changes:

1. Update the command for dispersing a blob:
   Current command:

   grpcurl -plaintext -d '{"data": "'$(tools/kzgpad/bin/kzgpad -e hello)'"}' \
   localhost:32003 disperser.Disperser/DisperseBlob

   Suggested command:

   REQUEST_ID=$(grpcurl -plaintext -d '{"data": "'$(../tools/kzgpad/bin/kzgpad -e hello)'"}' \
   localhost:32003 disperser.Disperser/DisperseBlob | jq -r .requestId)

   Reason: This change captures the REQUEST_ID directly in the command, making it easier for users to reference this ID in subsequent commands without needing to manually extract it.

2. Update the command for checking blob status:
   Current command:

   grpcurl -plaintext -d '{"request_id": "$REQUEST_ID"}' \
   localhost:32003 disperser.Disperser/GetBlobStatus

   Suggested command:

   grpcurl -plaintext -d "{\"request_id\": \"$REQUEST_ID\"}" \
   localhost:32003 disperser.Disperser/GetBlobStatus

   Reason: Using double quotes for the JSON string allows for proper variable interpolation, ensuring that the value of REQUEST_ID is correctly passed in the request.

Additional information.

Thank you for considering these changes!

[samlaf]

@l0g2 very much agree with you here, I had the same hiccups when first playing with these. May I suggest you put a quick PR up for this, I'll gladly accept it.