fix: Flatten sourceMap folder detection

CodeQL was flagging the second `else if`.
Looked at code and inlined the single use so it's not executed if
first condition is true.

bin/node-sass

@@ -204,14 +204,11 @@ function getOptions(args, options) {
       options.sourceMapOriginal = options.sourceMap;
     }
 
-    // check if sourceMap path ends with .map to avoid isDirectory false-positive
-    var sourceMapIsDirectory = options.sourceMapOriginal.indexOf('.map', options.sourceMapOriginal.length - 4) === -1 && isDirectory(options.sourceMapOriginal);
-
     if (options.sourceMapOriginal === 'true') {
       options.sourceMap = options.dest + '.map';
-    } else if (!sourceMapIsDirectory) {
+    } else if (!(options.sourceMapOriginal.indexOf('.map', options.sourceMapOriginal.length - 4) === -1 && isDirectory(options.sourceMapOriginal))) {
       options.sourceMap = path.resolve(options.sourceMapOriginal);
-    } else if (sourceMapIsDirectory) {
+    } else {
       if (!options.directory) {
         options.sourceMap = path.resolve(options.sourceMapOriginal, path.basename(options.dest) + '.map');
       } else {