Fix six quality findings from code review

sitecustomize.py:
- Restore _record_status count barrier: write the status file only after all
  patches have reported. middlewared.plugins.cloud_backup.restic is imported
  lazily (only when a backup task runs), so without this barrier verify would
  declare "all patches active" based solely on the B2 patch that fires at
  startup. Barrier now gates on _Finder._targets rather than the removed
  _PATCHES dict.
- Add comment in exec_module noting the if/elif must stay in sync with
  _Finder._targets, making the coupling visible.

patch_ui.py:
- Merge find_webui into find_bundle: previously find_bundle(None) would crash
  with os.walk(None) if main()'s guard were removed. Merged function returns
  a 3-tuple (webui_dir, path, content); webui_dir=None means no candidate
  directory found, path=None means directory found but pattern absent.
  main() still produces distinct messages for each failure mode.

create_task.py:
- Split triple-chained .get() in cmd_list_tasks into two lines; the or {}
  handling for None credentials was buried inside a one-liner.

uninstall.sh:
- Fix find loop: replace "for x in $(find ...)" with "while IFS= read -r"
  to handle paths containing spaces or newlines.
- Add #!/usr/bin/env shebang form to Python detection, matching apply.sh.
  Without this, uninstall on a system where middlewared uses the env form
  would silently leave sitecustomize.py in the wrong site-packages.

patch/create_task.py

@@ -139,7 +139,8 @@ def cmd_list_tasks(client, _args):
     print(f"{'ID':>4}  {'Enabled':<8}  {'Provider':<14}  Name")
     print("─" * 60)
     for t in sorted(tasks, key=lambda x: x["id"]):
-        ptype = (t.get("credentials") or {}).get("provider", {}).get("type", "?")
+        creds = t.get("credentials") or {}
+        ptype = creds.get("provider", {}).get("type", "?")
         enabled = "yes" if t.get("enabled") else "no"
         print(f"{t['id']:>4}  {enabled:<8}  {ptype:<14}  {t.get('description', '')}")