Everywhere: Use LibFileSystem where trivial

Author: https://github.com/cammo1123
Commit: 1d24f394c6
Pull-request: https://github.com/SerenityOS/serenity/pull/17789
Reviewed-by: https://github.com/AtkinsSJ
Reviewed-by: https://github.com/caoimhebyrne
Reviewed-by: https://github.com/kleinesfilmroellchen ✅
Reviewed-by: https://github.com/linusg
Reviewed-by: https://github.com/pascalpuffke
Reviewed-by: https://github.com/timschumi ✅

Userland/Libraries/LibGUI/FilePicker.cpp

@@ -7,8 +7,8 @@
 #include <AK/Function.h>
 #include <AK/LexicalPath.h>
 #include <LibConfig/Client.h>
-#include <LibCore/DeprecatedFile.h>
 #include <LibCore/StandardPaths.h>
+#include <LibFileSystem/FileSystem.h>
 #include <LibGUI/Action.h>
 #include <LibGUI/BoxLayout.h>
 #include <LibGUI/Button.h>
@@ -320,7 +320,7 @@ void FilePicker::on_file_return()
         path = LexicalPath::join(m_model->root_path(), path).string();
     }
 
-    bool file_exists = Core::DeprecatedFile::exists(path);
+    bool file_exists = FileSystem::exists(path);
 
     if (!file_exists && (m_mode == Mode::Open || m_mode == Mode::OpenFolder)) {
         MessageBox::show(this, DeprecatedString::formatted("No such file or directory: {}", m_filename_textbox->text()), "File not found"sv, MessageBox::Type::Error, MessageBox::InputType::OK);