Fix: ignore whitespaces pasted in EmotePopup search (#3730)

Co-authored-by: Felanbird <41973452+Felanbird@users.noreply.github.com>
Co-authored-by: pajlada <rasmus.karlsson@pajlada.com>

src/widgets/helper/TrimRegExpValidator.hpp

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <QRegularExpression>
+#include <QRegularExpressionValidator>
+
+namespace chatterino {
+
+class TrimRegExpValidator : public QRegularExpressionValidator
+{
+    Q_OBJECT
+
+public:
+    TrimRegExpValidator(const QRegularExpression &re,
+                        QObject *parent = nullptr);
+
+    QValidator::State validate(QString &input, int &pos) const override;
+};
+
+}  // namespace chatterino