Fix "clear filter" button appearing

What does this mr do?

The "clear filter" button had been appearing even when the submission didn't include any actual filters.

Actions taken to fix bug

Added a condition which checks whether the query params contain any filtering parameters before actually submitting them.

Does this MR meet the acceptance criteria?

• I have added a changelog entry to reflect the significant changes I made and the bug I fixed.
• A test was created to test the bug.
• I have updated the documentation accordingly.
• I adhere to the style guide.

src/main/java/nl/tudelft/ewi/queue/service/RequestTableService.java

@@ -15,9 +15,7 @@
  */
 package nl.tudelft.ewi.queue.service;
 
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
+import java.util.*;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
@@ -38,6 +36,7 @@ import org.springframework.util.LinkedMultiValueMap;
 import org.springframework.util.MultiValueMap;
 
 import com.google.common.collect.Lists;
+import com.google.common.collect.Sets;
 import com.querydsl.core.types.Predicate;
 import com.querydsl.core.types.dsl.BooleanExpression;
 
@@ -59,6 +58,9 @@ import com.querydsl.core.types.dsl.BooleanExpression;
 public class RequestTableService {
 	private static final String PREDICATE_POSTFIX = "_filter_predicate";
 	private static final String PARAMETERS_POSTFIX = "_filter_parameters";
+	private static final Set<String> FILTERS = Sets.newHashSet(
+			"lab.course", "lab", "assignment", "room", "assistant", "status", "requestType"
+	);
 
 	@Autowired
 	private RoomRepository roomRepository;
@@ -71,8 +73,8 @@ public class RequestTableService {
 
 	/**
 	 * Analyses the given parameters and performs an action based on it. If the parameters contain a 'clear'
-	 * attribute, the filters stored in the current session are removed. Otherwise, the given parameters and
-	 * predicate are stored in the current session.
+	 * attribute, the filters stored in the current session are removed. If the parameters do not contain a filtering
+	 * attribute, nothing is submitted. Otherwise, the given parameters and predicate are stored in the current session.
 	 *
 	 * @param request    The HttpServletRequest used to get the session.
 	 * @param parameters The parameters to store.
@@ -81,15 +83,14 @@ public class RequestTableService {
 	public void submitFilters(HttpServletRequest request,
 			MultiValueMap<String, String> parameters,
 			Predicate predicate) {
-		if (parameters == null) {
-			return;
-		}
 
-		String key = pathFromRequest(request);
-		if (parameters.containsKey("clear")) {
-			clearFilters(request, key);
-		} else {
-			storeFilters(request, key, parameters, predicate);
+		if (containsFilterParams(parameters)) {
+			String key = pathFromRequest(request);
+			if (parameters.containsKey("clear")) {
+				clearFilters(request, key);
+			} else {
+				storeFilters(request, key, parameters, predicate);
+			}
 		}
 	}
 
@@ -267,6 +268,15 @@ public class RequestTableService {
 				.orElse(new LinkedMultiValueMap<>());
 	}
 
+	/**
+	 * Checks whether the query parameters include filters.
+	 * @param parameters the query parameters of the request
+	 * @return true if there is at least one filtering query parameter
+	 */
+	private boolean containsFilterParams(MultiValueMap<String, String> parameters) {
+		return parameters != null && !(Sets.intersection(FILTERS, parameters.keySet())).isEmpty();
+	}
+
 	/**
 	 * Flatmaps a list of courses to a list of labs.
 	 *