Drop legacyConfigRoot as it is not necessary (#986) (#987)

(I'm currently going through the Quarkiverse extensions using legacy
config roots).

Co-authored-by: Guillaume Smet <[email protected]>

Author: github-actions[bot]

server/runtime/pom.xml

@@ -55,9 +55,6 @@
                                     <version>${quarkus.version}</version>
                                 </path>
                             </annotationProcessorPaths>
-                            <compilerArgs>
-                                <arg>-AlegacyConfigRoot=true</arg>
-                            </compilerArgs>
                         </configuration>
                     </execution>
                 </executions>