bugfix: Update parameter-metadata-accessor.ts to prevent TypeError: undefined…

[Makkalay]

TypeError: undefined is not an object (evaluating 'types[param.index]')

 class ParameterMetadataAccessor {
     explore(instance, prototype, method) {
         const types = Reflect.getMetadata(constants_1.PARAMTYPES_METADATA, instance, method.name);
         const routeArgsMetadata = Reflect.getMetadata(constants_1.ROUTE_ARGS_METADATA, instance.constructor, method.name) || {};
         const parametersWithType = (0, lodash_1.mapValues)((0, reverse_object_keys_util_1.reverseObjectKeys)(routeArgsMetadata), (param) => ({
             type: types[param.index],
                       ^
TypeError: undefined is not an object (evaluating 'types[param.index]')

PR Checklist

Please check if your PR fulfills the following requirements:

• [ x] The commit message follows our guidelines: https://github.com/nestjs/nest/blob/master/CONTRIBUTING.md
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

• [x ] Bugfix
• Feature
• Code style update (formatting, local variables)
• Refactoring (no functional changes, no api changes)
• Build related changes
• CI related changes
• Other... Please describe:

What is the current behavior?

TypeError: undefined is not an object (evaluating 'types[param.index]')

Issue Number: N/A

What is the new behavior?

Set default type to string

Does this PR introduce a breaking change?

• Yes
• [x ] No

Other information