Change MySQL blob column to longblob

[amika-sq]

Currently, each dialect defines the following column types for blobs:

• MySQL - blob - 64Kb limit
• Postgres - bytea - 1 GB limit
• SQLite - blob - 1 GB limit (by default, we can make it go up to 2GB)

MySQL has a LONGBLOB column type, which has a capacity of ~4GB, bringing it more inline with the other dialects.

[amika-sq]

Relevant area of code:
https://github.com/TBD54566975/dwn-sql-store/blob/main/src/dialect/mysql-dialect.ts

I'm currently having environment issues, but it should be something like the following to enable:

return builder.addColumn(columnName, sql`longblob`, callback);

[aniketh-varma]

Hey @amika-sq, is this issue still relevant?