Enable ESLint rule no-case-declarations (#2113)

## Description:

This PR enables the ESLint rule `no-case-declarations`.
Fixes #1791 

The issue was already assigned, but since there hasn’t been any activity
for about a month, I decided to open this PR.

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I process any text displayed to the user through translateText()
and I've added it to the en.json file
- [x] I have added relevant tests to the test directory
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced

## Please put your Discord username so you can be contacted if a bug or
regression is found:

aotumuri

eslint.config.js

@@ -42,7 +42,6 @@ export default [
       "@typescript-eslint/no-explicit-any": "off",
       "@typescript-eslint/no-unused-expressions": "off",
       "@typescript-eslint/no-unused-vars": "off",
-      "no-case-declarations": "off",
     },
   },
   {
@@ -50,6 +49,7 @@ export default [
       // Enable rules
       "@typescript-eslint/prefer-nullish-coalescing": "error",
       eqeqeq: "error",
+      "no-case-declarations": "error",
     },
   },
 ];

src/client/graphics/layers/UILayer.ts

@@ -312,7 +312,7 @@ export class UILayer implements Layer {
       return 1;
     }
     switch (unit.type()) {
-      case UnitType.Construction:
+      case UnitType.Construction: {
         const constructionType = unit.constructionType();
         if (constructionType === undefined) {
           return 1;
@@ -326,7 +326,7 @@ export class UILayer implements Layer {
           (this.game.ticks() - unit.createdAt()) /
           (constDuration === 0 ? 1 : constDuration)
         );
-
+      }
       case UnitType.MissileSilo:
       case UnitType.SAMLauncher:
         return unit.missileReadinesss();

src/core/configuration/PastelTheme.ts

@@ -95,7 +95,7 @@ export class PastelTheme implements Theme {
     }
     switch (gm.terrainType(tile)) {
       case TerrainType.Ocean:
-      case TerrainType.Lake:
+      case TerrainType.Lake: {
         const w = this.water.rgba;
         if (gm.isShoreline(tile) && gm.isWater(tile)) {
           return this.shorelineWater;
@@ -105,7 +105,7 @@ export class PastelTheme implements Theme {
           g: Math.max(w.g - 10 + (11 - Math.min(mag, 10)), 0),
           b: Math.max(w.b - 10 + (11 - Math.min(mag, 10)), 0),
         });
-
+      }
       case TerrainType.Plains:
         return colord({
           r: 190,

src/core/configuration/PastelThemeDark.ts

@@ -16,7 +16,7 @@ export class PastelThemeDark extends PastelTheme {
     }
     switch (gm.terrainType(tile)) {
       case TerrainType.Ocean:
-      case TerrainType.Lake:
+      case TerrainType.Lake: {
         const w = this.darkWater.rgba;
         if (gm.isShoreline(tile) && gm.isWater(tile)) {
           return this.darkShorelineWater;
@@ -29,6 +29,7 @@ export class PastelThemeDark extends PastelTheme {
           });
         }
         return this.darkWater;
+      }
       case TerrainType.Plains:
         return colord({
           r: 140,