ios: avoid system default keychain writes

.gitea/workflows/testflight-release.yml

@@ -149,7 +149,6 @@ jobs:
             security list-keychains -s "${keychain_name}"
           fi
           security default-keychain -d user -s "${keychain_name}"
-          security default-keychain -s "${keychain_name}"
           keychain_path="$(security list-keychains -d user | sed 's/[ "]//g' | head -n 1)"
           security find-identity -v -p codesigning "${keychain_path}"
           security find-identity -v -p codesigning
@@ -185,7 +184,6 @@ jobs:
           security list-keychains -d user -s "${SYBIL_SIGNING_KEYCHAIN_PATH}" $(security list-keychains -d user | sed 's/[ "]//g')
           security default-keychain -d user -s "${SYBIL_SIGNING_KEYCHAIN_PATH}"
           security list-keychains -s "${SYBIL_SIGNING_KEYCHAIN_PATH}" $(security list-keychains | sed 's/[ "]//g')
-          security default-keychain -s "${SYBIL_SIGNING_KEYCHAIN_PATH}"
           security find-identity -v -p codesigning "${SYBIL_SIGNING_KEYCHAIN_PATH}"
           security find-identity -v -p codesigning