[SPC] Remove prefix from SPC test names (#31675)

Tests are already in the SPC folder, so don't need a prefix - and removing it
substantially shortens the filenames!
diff --git a/secure-payment-confirmation/secure-payment-confirmation-authentication-accepted.https.html b/secure-payment-confirmation/authentication-accepted.https.html
similarity index 100%
rename from secure-payment-confirmation/secure-payment-confirmation-authentication-accepted.https.html
rename to secure-payment-confirmation/authentication-accepted.https.html
diff --git a/secure-payment-confirmation/secure-payment-confirmation-authentication-cross-origin.sub.https.html b/secure-payment-confirmation/authentication-cross-origin.sub.https.html
similarity index 100%
rename from secure-payment-confirmation/secure-payment-confirmation-authentication-cross-origin.sub.https.html
rename to secure-payment-confirmation/authentication-cross-origin.sub.https.html
diff --git a/secure-payment-confirmation/secure-payment-confirmation-authentication-icon-data-url.https.html b/secure-payment-confirmation/authentication-icon-data-url.https.html
similarity index 100%
rename from secure-payment-confirmation/secure-payment-confirmation-authentication-icon-data-url.https.html
rename to secure-payment-confirmation/authentication-icon-data-url.https.html
diff --git a/secure-payment-confirmation/secure-payment-confirmation-authentication-in-iframe.sub.https.html b/secure-payment-confirmation/authentication-in-iframe.sub.https.html
similarity index 100%
rename from secure-payment-confirmation/secure-payment-confirmation-authentication-in-iframe.sub.https.html
rename to secure-payment-confirmation/authentication-in-iframe.sub.https.html
diff --git a/secure-payment-confirmation/secure-payment-confirmation-authentication-invalid-icon.https.html b/secure-payment-confirmation/authentication-invalid-icon.https.html
similarity index 100%
rename from secure-payment-confirmation/secure-payment-confirmation-authentication-invalid-icon.https.html
rename to secure-payment-confirmation/authentication-invalid-icon.https.html
diff --git a/secure-payment-confirmation/secure-payment-confirmation-authentication-rejected.https.html b/secure-payment-confirmation/authentication-rejected.https.html
similarity index 100%
rename from secure-payment-confirmation/secure-payment-confirmation-authentication-rejected.https.html
rename to secure-payment-confirmation/authentication-rejected.https.html
diff --git a/secure-payment-confirmation/secure-payment-confirmation-constructor.https.html b/secure-payment-confirmation/constructor.https.html
similarity index 100%
rename from secure-payment-confirmation/secure-payment-confirmation-constructor.https.html
rename to secure-payment-confirmation/constructor.https.html
diff --git a/secure-payment-confirmation/secure-payment-confirmation-enrollment.https.html b/secure-payment-confirmation/enrollment.https.html
similarity index 100%
rename from secure-payment-confirmation/secure-payment-confirmation-enrollment.https.html
rename to secure-payment-confirmation/enrollment.https.html