delete.namespace doesn't detect dependencies sometimes

[ceedubs]

Here is an example where I would expect delete.namespace lib.http_old to complain that HttpResponse.fromStream and HttpRequest.encode were in use and couldn't be deleted:

@stew/httpclient/fix_encoding> todo                                                                                                                                                                               

  ✅
  
  No conflicts or edits in progress.
InputPattern: 69.5 ms (cpu), 70.9 ms (system)
@stew/httpclient/fix_encoding> namespace.dependencies

  This namespace has no external dependencies.
InputPattern: 2.91 s (cpu), 2.90 s (system)
@stew/httpclient/fix_encoding> delete.namespace lib.http                                                                                                                                                          
lib.http          lib.http_old
@stew/httpclient/fix_encoding> delete.namespace lib.http_old
updateRoot: 31.9 ms (cpu), 24.5 ms (system)

  Done.
InputPattern: 1.33 s (cpu), 1.32 s (system)
@stew/httpclient/fix_encoding> namespace.dependencies

  External dependency                                                                                                       Dependents in .__projects._a9cb071e_8aed_411e_9f68_9d30faa7439b.branches._15fc3a73_22a4_44b4_ac03_c8388626afce
  __projects._ae49ffd9_dcb6_4f41_8276_0b1f5490a975.branches._fcd56890_ec5e_466a_af80_a89213b7eed1.HttpResponse.fromStream   1. Http.configuredHandler
                                                                                                                            
  __projects._ae49ffd9_dcb6_4f41_8276_0b1f5490a975.branches._fcd56890_ec5e_466a_af80_a89213b7eed1.HttpRequest.encode        1. Http.configuredHandler
                                                                                                                            2. proxy.connectRequest.tests.example1