feat(RM-40): MessageID & ChannelID as nullable

[DanPlayz0]

This pull request introduces changes to the panels.go file, primarily to allow message_id and channel_id fields to be nullable, improving flexibility in handling panel data. Key updates include modifying the schema, struct definitions, and related methods to support nullable values.

Schema and struct updates:

• Changed the message_id and channel_id fields in the Panel struct to be pointers (*uint64) to allow null values. (panels.goL14-R15)
• Updated the database schema for the panels table to make message_id and channel_id nullable by setting their default to NULL. (panels.goL59-R60)

Method updates:

• Modified UpdateMessageId to accept a pointer (*uint64) for message_id to handle nullable values. (panels.goL601-R601)
• Added a new method UpdateChannelId to update the channel_id field, also supporting nullable values. (panels.goR612-R622)

Migration:

• This pull request does require an update to the database to allow nullable fields (channel_id & message_id)

  ALTER TABLE panels ALTER COLUMN "channel_id" DROP NOT NULL;
  ALTER TABLE panels ALTER COLUMN "message_id" DROP NOT NULL;

Notes

This PR was originally created in May, and was later updated; original changes can be found by comparing commits 17762cd7d39ae3c02a4746978cff5021a749f80b & e113c4330d33cc2cc885a240c0dd4427e052eb29