feat: update lti API to pick config via launch data

Note that this uses config_id (the UUID) not config.id (the int)

This required a way to get config_id if we only have the block.

And it means that we are more likely to go through load_block_as_user
because we have not created the config off the block even when calling
from the block (since the block has to go through that config ID).

A lot of tests had to be updated to have more complete configuration
setup because config_id is now load bearing.