Move T1OO filter to new permissions system

[evansd]

The current T1OO filtering logic predates the more generalised permissions system and instead uses an extra query parameter on the database URL:

ehrql/ehrql/backends/tpp.py

Lines 114 to 118 in cbb7628

	def modify_dsn(self, dsn):
	"""
	Removes the `opensafely_include_t1oo` parameter if present and uses it to set
	the `include_t1oo` attribute accordingly
	"""

Now that we need to implement parallel logic for EMIS this is a good point at which to move the TPP logic to use the permissions system. We certainly don't want to be trying to implement the query parameter version in EMIS, and having divergent implementations isn't ideal.

Here's an outline of a plan for doing so. I've only mention the production code changes, but each of these will require test changes as well. Where the code comments mention specific bits of documentation that need updating then that should be done as well. Each step presumes that the previous step has been merged and deployed.

1. Update Job Server to send the right permissions

The first step is to update Job Server so that it sends the right permissions (while also leaving the old code in place). That involves adding an analysis_scope_for_project function (parallel to the one for ndoo) to the t100 module. And then including the t1oo module in the list of "population permission" modules here. The permission name should be include_t1oo.

2. Update ehrQL to respect both old and new permissions

That means adding a line here:

ehrql/ehrql/backends/tpp.py

Line 136 in cbb7628

include_ndoo = "include_ndoo" in self.permissions

include_t1oo = self.include_t1oo or "include_t1oo" in self.permissions

And changing self.include_t1oo to include_t1oo here:

ehrql/ehrql/backends/tpp.py

Line 152 in cbb7628

if not self.include_t1oo:

3. Remove old code from Job Server

This method can just be replaced with return "default", and the project_is_permitted_to_use_t1oo_data function removed entirely.

4. Remove old code from ehrQL

We can then remove the entire modify_dsn method, and in fact remove the modify_dsn hook from BaseBackend altogether. The self.include_t1oo attribute can go as well.

5. Tidy up

We can remove the INCLUDE_T1OO_DATABASE_URL from the secrets template. And remove the config value from ~/config/02_secrets.env in the TPP backend as well.

We can remove include_t1oo from the VALID_DATABASE_NAMES here.

[rebkwok]

• And remove the config value from ~/config/02_secrets.env in the TPP backend as well