Bump pdfbox from 2.0.15 to 2.0.24 in /server

Bumps pdfbox from 2.0.15 to 2.0.24.

---
updated-dependencies:
- dependency-name: org.apache.pdfbox:pdfbox
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

server/pom.xml

@@ -164,7 +164,7 @@
         <dependency>
             <groupId>org.apache.pdfbox</groupId>
             <artifactId>pdfbox</artifactId>
-            <version>2.0.15</version>
+            <version>2.0.24</version>
         </dependency>
         <dependency>
             <groupId>org.apache.pdfbox</groupId>