Split macro-condition-video.cpp UI into per-widget files

This makes it easier to conditionally exclude video-edit-object.cpp
from the build when OpenCV >= 5 drops CascadeClassifier support.

plugins/video/video-edit-brightness.cpp

@@ -0,0 +1,53 @@
+#include "macro-condition-video.hpp"
+
+#include <QTimer>
+#include <QVBoxLayout>
+
+namespace advss {
+
+BrightnessEdit::BrightnessEdit(QWidget *parent,
+			       const std::shared_ptr<MacroConditionVideo> &data)
+	: QWidget(parent),
+	  _threshold(new SliderSpinBox(
+		  0., 1.,
+		  obs_module_text(
+			  "AdvSceneSwitcher.condition.video.brightnessThreshold"),
+		  obs_module_text(
+			  "AdvSceneSwitcher.condition.video.brightnessThresholdDescription"))),
+	  _current(new QLabel),
+	  _entryData(data)
+{
+	auto layout = new QVBoxLayout;
+	layout->setContentsMargins(0, 0, 0, 0);
+	layout->addWidget(_threshold);
+	layout->addWidget(_current);
+	setLayout(layout);
+
+	QWidget::connect(
+		_threshold,
+		SIGNAL(DoubleValueChanged(const NumberVariable<double> &)),
+		this,
+		SLOT(BrightnessThresholdChanged(
+			const NumberVariable<double> &)));
+	QWidget::connect(&_timer, &QTimer::timeout, this,
+			 &BrightnessEdit::UpdateCurrentBrightness);
+	_timer.start(1000);
+
+	_threshold->SetDoubleValue(_entryData->_brightnessThreshold);
+	_loading = false;
+}
+
+void BrightnessEdit::UpdateCurrentBrightness()
+{
+	QString text = obs_module_text(
+		"AdvSceneSwitcher.condition.video.currentBrightness");
+	_current->setText(text.arg(_entryData->GetCurrentBrightness()));
+}
+
+void BrightnessEdit::BrightnessThresholdChanged(const DoubleVariable &value)
+{
+	GUARD_LOADING_AND_LOCK();
+	_entryData->_brightnessThreshold = value;
+}
+
+} // namespace advss