### Description

In [TransportSamlInitiateSingleSignOnActionTests.java](https://github.com/elastic/elasticsearch/pull/98882/files#diff-26733d11b06442213a040cc3d5c89595300ec813bb31076874afa38ef2ad3b91),  `/api/security/v1/saml` (deprecated) should be replaced with /api/security/saml/callback

In https://github.com/elastic/kibana/blob/b33effa182bcb7c9620c5435ab252d8067732655/x-pack/plugins/security/server/routes/authentication/saml.ts#L27

/api/security/saml/callback is the correct URL,
while /api/security/v1/saml is the deprecated URL.

Related to https://github.com/elastic/cloud-on-k8s/issues/7118
x-pack/plugin/identity-provider/src/test/java/org/elasticsearch/xpack/idp/action/TransportSamlInitiateSingleSignOnActionTests.java
final SamlInitiateSingleSignOnRequest request = new SamlInitiateSingleSignOnRequest();
        request.setSpEntityId("https://sp.some.org");
        request.setAssertionConsumerService("https://sp.some.org/api/security/v1/saml");
        final PlainActionFuture<SamlInitiateSingleSignOnResponse> future = new PlainActionFuture<>();
        final TransportSamlInitiateSingleSignOnAction action = setupTransportAction(false);
        action.doExecute(mock(Task.class), request, future);
        Exception e = expectThrows(Exception.class, () -> future.get());
        assertThat(e.getCause().getMessage(), containsString("Request is missing secondary authentication"));
    }
    public void testGetResponseForNotRegisteredSpInIdpInitiated() throws Exception {
        final SamlInitiateSingleSignOnRequest request = new SamlInitiateSingleSignOnRequest();
        request.setSpEntityId("https://sp2.other.org");
        request.setAssertionConsumerService("https://sp2.some.org/api/security/v1/saml");
        final PlainActionFuture<SamlInitiateSingleSignOnResponse> future = new PlainActionFuture<>();
        final TransportSamlInitiateSingleSignOnAction action = setupTransportAction(true);
        action.doExecute(mock(Task.class), request, future);
        Exception e = expectThrows(Exception.class, () -> future.get());
        assertThat(e.getCause().getMessage(), containsString("https://sp2.other.org"));
        assertThat(e.getCause().getMessage(), containsString("is not known to this Identity Provider"));
    }
    public void testGetResponseWithoutSecondaryAuthenticationInSpInitiatedFlow() throws Exception {
        final SamlInitiateSingleSignOnRequest request = new SamlInitiateSingleSignOnRequest();
        request.setSpEntityId("https://sp.some.org");
        request.setAssertionConsumerService("https://sp.some.org/saml/acs");
        final String requestId = randomAlphaOfLength(12);
        final SamlAuthenticationState samlAuthenticationState = new SamlAuthenticationState();
        samlAuthenticationState.setAuthnRequestId(requestId);
        request.setSamlAuthenticationState(samlAuthenticationState);
        final PlainActionFuture<SamlInitiateSingleSignOnResponse> future = new PlainActionFuture<>();
        final TransportSamlInitiateSingleSignOnAction action = setupTransportAction(false);