fix(#774): use GET for plugin rescan to match backend (#788)

Co-authored-by: M57 <hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/data/remote/HermesApiService.kt

@@ -525,7 +525,7 @@ interface HermesApiService {
         @Path("name", encoded = true) name: String,
     ): Response<Unit>
 
-    @POST("api/dashboard/plugins/rescan")
+    @GET("api/dashboard/plugins/rescan")
     suspend fun rescanPlugins(): Response<Unit>
 
     @PUT("api/dashboard/plugin-providers")