Fix: Correct OpenSAML 5.x Documentation

- Fixed invalid XML tags in dependency examples.
- Corrected typo in `<artifactId>` ("opensaml-saml-imple" -> "opensaml-saml-impl").
- Excluded all OpenSAML 4.x dependencies.
- Removed redundant dependencies (`opensaml-core-api` and `opensaml-core-impl`) as they are transitively included in `opensaml-saml-api` and `opensaml-saml-impl`.

Closes gh-16191

docs/modules/ROOT/pages/servlet/saml2/opensaml.adoc

@@ -25,44 +25,27 @@ Maven::
 +
 [source,maven,role="primary"]
 ----
-<dependencyManagement>
-    <dependencies>
-        <dependency>
-            <groupId>org.opensaml</groupId>
-            <artifactId>opensaml-core-api</artifactId>
-            <version>5.1.2</version>
-        </dependency>
-        <dependency>
-            <groupId>org.opensaml</groupId>
-            <artifactId>opensaml-core-impl</artifactId>
-            <version>5.1.2</version>
-        </dependency>
-        <dependency>
-            <groupId>org.opensaml</groupId>
-            <artifactId>opensaml-saml-api</artifactId>
-            <version>5.1.2</version>
-        </dependency>
-        <dependency>
-            <groupId>org.opensaml</groupId>
-            <artifactId>opensaml-saml-impl</artifactId>
-            <version>5.1.2</version>
-        </dependency>
-    </dependencies>
-</dependencyManagement>
-
-// ...
-
 <dependencies>
     <dependency>
         <groupId>org.springframework.security</groupId>
         <artifactId>spring-security-saml2-service-provider</artifactId>
         <exclusions>
             <exclusion>
                 <groupId>org.opensaml</groupId>
-                <artifactId>opensaml-core</artifactId>
+                <artifactId>*</artifactId>
             </exclusion>
         </exclusions>
     </dependency>
+    <dependency>
+        <groupId>org.opensaml</groupId>
+        <artifactId>opensaml-saml-api</artifactId>
+        <version>5.1.2</version>
+    </dependency>
+    <dependency>
+        <groupId>org.opensaml</groupId>
+        <artifactId>opensaml-saml-impl</artifactId>
+        <version>5.1.2</version>
+    </dependency>
 </dependencies>
 ----