Fix flaky gap-analysis tests connecting to real Redis instead of mock - #1010

Summary

Fixes #1009 — several tests in web_main_test.py covering
/rest/v1/map_analysis were silently connecting to a real local Redis
instance instead of the mock, causing flaky, order-dependent,
environment-dependent test failures.

Root cause

The tests patched redis.from_url (the third-party library's URL-based
connection factory), but application/utils/redis.py's connect()
function has three possible branches and takes a different, unmocked
one — redis.StrictRedis(host=..., port=...) — whenever REDIS_HOST and
REDIS_PORT environment variables are set. These are set by default for
anyone following this project's own documented local setup
(.env.example sets REDIS_HOST=localhost / REDIS_PORT=6379, loaded
automatically via load_dotenv() in cre.py). So the standard,
documented local dev setup silently defeated the mock for anyone running
these tests.

The fix

Patch application.utils.redis.connect directly, at its actual point of
use in web_main.py, instead of patching one specific branch
(redis.from_url) of its internal implementation. This makes the tests
immune to which branch connect() takes based on environment variables —
there's now exactly one thing to mock, and it's the thing that's actually
called.

# before
@patch.object(redis, "from_url")

# after
@patch.object(app_redis, "connect")