Fix quality issues (#1827)

Author: guillaume-dequenne

python-frontend/src/main/java/org/sonar/python/semantic/ProjectLevelSymbolTable.java

@@ -24,7 +24,6 @@
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
-import java.util.Optional;
 import java.util.Set;
 import java.util.function.Function;
 import java.util.stream.Collectors;

python-frontend/src/main/java/org/sonar/python/semantic/v2/SymbolV2.java

@@ -21,7 +21,6 @@
 
 import java.util.ArrayList;
 import java.util.List;
-import javax.annotation.Nullable;
 import org.sonar.api.Beta;
 import org.sonar.plugins.python.api.tree.Name;
 import org.sonar.python.tree.NameImpl;

python-frontend/src/main/java/org/sonar/python/types/v2/ModuleType.java

@@ -21,7 +21,6 @@
 
 import java.util.HashMap;
 import java.util.Map;
-import java.util.Objects;
 import java.util.Optional;
 import javax.annotation.CheckForNull;
 import javax.annotation.Nullable;

python-frontend/src/test/java/org/sonar/python/semantic/v2/TypeInferenceV2Test.java

@@ -21,7 +21,6 @@
 
 import java.util.Collection;
 import java.util.Comparator;
-import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -31,7 +30,6 @@
 import org.junit.jupiter.api.Disabled;
 import org.junit.jupiter.api.Test;
 import org.sonar.plugins.python.api.PythonFile;
-import org.sonar.plugins.python.api.symbols.Symbol;
 import org.sonar.plugins.python.api.tree.AssignmentStatement;
 import org.sonar.plugins.python.api.tree.CallExpression;
 import org.sonar.plugins.python.api.tree.ClassDef;