fix(e2e): let the install sweep fail when a repository fails

Both sweeps passed `--silent`, which does not quiet the output it sounds like
it quiets: the warning list is printed under `not quiet`, while `silent` guards
only `raise SystemExit(1)` in actions/install/__init__.py and in
actions/update/manager.py. The failures were therefore in the log, the process
exited 0, and the test asserted success on a run that had installed nothing for
two repositories.

The module docstring already promises the test passes only if both commands
complete successfully. Dropping the flag makes that sentence true again; it is
how portfolio and ldap-schema-manager went unnoticed, and both are fixed in the
two preceding commits.

The flag itself is untouched and still available on the CLI.

Verified: the sweep runs green without it in the arch image, and hid two
failures with it.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

tests/e2e/test_update_all_no_system.py

@@ -93,7 +93,6 @@ class TestIntegrationUpdateAllshallowNoSystem(unittest.TestCase):
                 "--clone-mode",
                 "shallow",
                 "--no-verification",
-                "--silent",
             ]
             self._run_cmd(["pkgmgr", *args], label="pkgmgr", env=env)
             pkgmgr_help_debug()
@@ -108,7 +107,6 @@ class TestIntegrationUpdateAllshallowNoSystem(unittest.TestCase):
                 "--clone-mode",
                 "shallow",
                 "--no-verification",
-                "--silent",
             ]
             self._run_cmd(
                 ["nix", "run", ".#pkgmgr", "--", *args],