Upgrade Spring Boot (#140)

The new version has upgraded `json-smart` so the override is no longer necessary.

## How to test
1. Log in and click around as different users
2. Enable Daisy integration (both `DEV` and `DAISY-INTEGRATION` Maven profiles)
3. Go to "Admin / Users / Import" and import someone (verify JSON parsing)

Reviewed-on: #140
Reviewed-by: Nico Athanassiadis <nico@dsv.su.se>
Co-authored-by: Andreas Svanberg <andreass@dsv.su.se>
Co-committed-by: Andreas Svanberg <andreass@dsv.su.se>

pom.xml

@@ -28,12 +28,7 @@
         <querydsl.version>5.0.0</querydsl.version>
         <poi.version>5.4.0</poi.version>
 
-        <!--
-            When updating spring-boot check if the transitive dependency on json-smart has been
-            updated to 2.5.2 or later.
-            If so, remove the dependency managed version of json-smart
-        -->
-        <spring.boot.version>3.4.1</spring.boot.version>
+        <spring.boot.version>3.4.3</spring.boot.version>
         <springdoc.openapi.version>2.8.3</springdoc.openapi.version>
 
         <!-- Database stuff -->
@@ -115,21 +110,6 @@
                 <version>32.0.1-jre</version>
             </dependency>
 
-            <dependency>
-                <!--
-                2.5.1 is brought in transitively by
-                  spring-boot-starter-oauth2-client
-                    spring-security-oauth2-client
-                      oauth2-oidc-sdk
-                        json-smart
-                it has a known security vulnerability that's fixed in 2.5.2
-                should be removed when spring-boot-starter-oauth2-client is updated
-                -->
-                <groupId>net.minidev</groupId>
-                <artifactId>json-smart</artifactId>
-                <version>2.5.2</version>
-            </dependency>
-
             <dependency>
                 <groupId>org.apache.poi</groupId>
                 <artifactId>poi</artifactId>