Fix eslint rule 'prefer-const' in gui/campaigns

eslint --no-config-lookup --fix --rule '"prefer-const": 1' \
    binaries/data/mods/public/gui/campaigns

Ref: #7812
Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>

binaries/data/mods/public/gui/campaigns/default_menu/CampaignMenu.js

@@ -172,9 +172,9 @@ class CampaignMenu extends AutoWatcher
 	displayLevelsList()
 	{
 		let list = [];
-		for (let key in this.run.template.Levels)
+		for (const key in this.run.template.Levels)
 		{
-			let level = this.run.template.Levels[key];
+			const level = this.run.template.Levels[key];
 
 			if (!this.shouldShowLevel(level))
 				continue;
@@ -212,7 +212,7 @@ class CampaignMenu extends AutoWatcher
 			return;
 		}
 
-		let level = this.getSelectedLevelData();
+		const level = this.getSelectedLevelData();
 
 		Engine.GetGUIObjectByName("scenarioName").caption = this.getLevelName(level);
 		Engine.GetGUIObjectByName("scenarioDesc").caption = this.getLevelDescription(level);

binaries/data/mods/public/gui/campaigns/default_menu/endgame/endgame.js

@@ -5,7 +5,7 @@
 
 function init(endGameData)
 {
-	let run = CampaignRun.getCurrentRun();
+	const run = CampaignRun.getCurrentRun();
 	if (endGameData.won)
 		markLevelComplete(run, endGameData.initData.levelID);
 }

binaries/data/mods/public/gui/campaigns/load_modal/LoadModal.js

@@ -62,11 +62,11 @@ class LoadModal extends AutoWatcher
 
 	getRuns()
 	{
-		let out = [];
-		let files = Engine.ListDirectoryFiles("saves/campaigns/", "*.0adcampaign", false);
-		for (let file of files)
+		const out = [];
+		const files = Engine.ListDirectoryFiles("saves/campaigns/", "*.0adcampaign", false);
+		for (const file of files)
 		{
-			let name = file.replace("saves/campaigns/", "").replace(".0adcampaign", "");
+			const name = file.replace("saves/campaigns/", "").replace(".0adcampaign", "");
 			try
 			{
 				out.push(new CampaignRun(name).load());
@@ -82,8 +82,8 @@ class LoadModal extends AutoWatcher
 
 	loadCampaign()
 	{
-		let filename = this.currentRuns[this.selectedRun].filename;
-		let run = new CampaignRun(filename)
+		const filename = this.currentRuns[this.selectedRun].filename;
+		const run = new CampaignRun(filename)
 			.load()
 			.setCurrent();
 
@@ -97,7 +97,7 @@ class LoadModal extends AutoWatcher
 		if (this.selectedRun === -1)
 			return;
 
-		let run = this.currentRuns[this.selectedRun];
+		const run = this.currentRuns[this.selectedRun];
 
 		const buttonIndex = await messageBox(
 			400, 200,

binaries/data/mods/public/gui/campaigns/new_modal/NewCampaignModal.js

@@ -20,8 +20,8 @@ class NewCampaignModal
 
 	createAndStartCampaign()
 	{
-		let filename = this.template.identifier + "_" + Date.now() + "_" + Math.floor(Math.random()*100000);
-		let run = new CampaignRun(filename)
+		const filename = this.template.identifier + "_" + Date.now() + "_" + Math.floor(Math.random()*100000);
+		const run = new CampaignRun(filename)
 			.setTemplate(this.template)
 			.setMeta(Engine.GetGUIObjectByName('runDescription').caption)
 			.save()