Fix apparent typo in getStringMappingType (#51248)

Author: jakebailey

src/compiler/checker.ts

@@ -15709,7 +15709,7 @@ namespace ts {
                 type.flags & TypeFlags.TemplateLiteral ? getTemplateLiteralType(...applyTemplateStringMapping(symbol, (type as TemplateLiteralType).texts, (type as TemplateLiteralType).types)) :
                 // Mapping<Mapping<T>> === Mapping<T>
                 type.flags & TypeFlags.StringMapping && symbol === type.symbol ? type :
-                type.flags & (TypeFlags.Any | TypeFlags.String || type.flags & TypeFlags.StringMapping) || isGenericIndexType(type) ? getStringMappingTypeForGenericType(symbol, type) :
+                type.flags & (TypeFlags.Any | TypeFlags.String | TypeFlags.StringMapping) || isGenericIndexType(type) ? getStringMappingTypeForGenericType(symbol, type) :
                 // This handles Mapping<`${number}`> and Mapping<`${bigint}`>
                 isPatternLiteralPlaceholderType(type) ? getStringMappingTypeForGenericType(symbol, getTemplateLiteralType(["", ""], [type])) :
                 type;