Use runner login keychain for CI signing

ios/fastlane/Fastfile

@@ -1,4 +1,3 @@
-require "fileutils"
 require "shellwords"
 
 default_platform(:ios)
@@ -33,48 +32,28 @@ def release_version
 end
 
 platform :ios do
+  private_lane :cleanup_ci_signing_identity do
+    next unless ENV["CI"]
+
+    sh("security delete-identity -Z #{SIGNING_IDENTITY_SHA1.shellescape} || true", log: false)
+  end
+
   private_lane :prepare_ci_keychain do
     next unless ENV["CI"]
 
-    keychain_path = File.expand_path("../build/ci/sybil-signing.keychain", __dir__)
-    keychain_password = ENV["MATCH_KEYCHAIN_PASSWORD"].to_s
-    keychain_password = "sybil-ci-keychain-password" unless present?(keychain_password)
-
-    FileUtils.mkdir_p(File.dirname(keychain_path))
-
-    create_keychain(
-      path: keychain_path,
-      password: keychain_password,
-      default_keychain: false,
-      unlock: true,
-      timeout: 3600,
-      lock_after_timeout: false,
-      add_to_search_list: true
-    )
-
-    resolved_keychain_path = ["#{keychain_path}-db", keychain_path].find { |path| File.exist?(path) } || keychain_path
-
-    sh("security list-keychains -d user -s #{resolved_keychain_path.shellescape}", log: false)
-
-    ENV["MATCH_KEYCHAIN_NAME"] = resolved_keychain_path
-    ENV["MATCH_KEYCHAIN_PASSWORD"] = keychain_password
+    cleanup_ci_signing_identity
+    ENV.delete("MATCH_KEYCHAIN_NAME")
+    ENV.delete("MATCH_KEYCHAIN_PASSWORD")
   end
 
   private_lane :verify_ci_signing_identity do
     next unless ENV["CI"]
 
-    keychain_path = ENV.fetch("MATCH_KEYCHAIN_NAME")
-    keychain_password = ENV.fetch("MATCH_KEYCHAIN_PASSWORD")
-
-    sh("security unlock-keychain -p #{keychain_password.shellescape} #{keychain_path.shellescape}", log: false)
-    sh("security list-keychains -d user -s #{keychain_path.shellescape}", log: false)
-    sh("security set-key-partition-list -S apple-tool:,apple:,codesign: -s -k #{keychain_password.shellescape} #{keychain_path.shellescape}", log: false)
-
-    identities = sh("security find-identity -v -p codesigning #{keychain_path.shellescape}", log: false)
+    identities = sh("security find-identity -v -p codesigning", log: false)
     UI.message(identities)
 
     unless identities.include?(SIGNING_IDENTITY_NAME)
-      UI.user_error!("The CI keychain does not contain the expected Apple Distribution signing identity")
+      UI.user_error!("The runner login keychain does not contain the expected Apple Distribution signing identity")
     end
   end
 
@@ -143,9 +122,6 @@ platform :ios do
       xcodeproj: PROJECT_FILE
     )
 
-    sync_match_signing(readonly: true)
-    verify_ci_signing_identity
-
     build_options = {
       project: PROJECT_FILE,
       scheme: SCHEME,
@@ -159,12 +135,17 @@ platform :ios do
 
     if ENV["CI"]
       build_options[:xcargs] = [
-        "CODE_SIGN_IDENTITY=#{SIGNING_IDENTITY_SHA1.shellescape}",
-        "OTHER_CODE_SIGN_FLAGS=#{("--keychain #{ENV.fetch("MATCH_KEYCHAIN_NAME")}").shellescape}"
+        "CODE_SIGN_IDENTITY=#{SIGNING_IDENTITY_SHA1.shellescape}"
       ].join(" ")
     end
 
+    begin
+      sync_match_signing(readonly: true)
+      verify_ci_signing_identity
       build_app(build_options)
+    ensure
+      cleanup_ci_signing_identity
+    end
 
     upload_to_testflight(
       api_key: api_key,