[iOS][Credential-Provider] Remove unused dep

Bug: N/A
Change-Id: I3d3e3e997ef328f696a31a7056cf1ef942c47941
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2062370
Auto-Submit: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Reviewed-by: David Jean <djean@chromium.org>
Commit-Queue: Javier Ernesto Flores Robles <javierrobles@chromium.org>
Cr-Commit-Position: refs/heads/master@{#743889}

ios/chrome/credential_provider_extension/BUILD.gn

@@ -45,7 +45,6 @@ ios_appex_bundle("credential_provider_extension") {
 
   deps = [
     ":system_strings",
-    "//base",
     "//ios/chrome/common/colors",
     "//ios/chrome/credential_provider_extension/resources",
     "//ios/chrome/credential_provider_extension/ui",