Params validation

### Prerequisites

- [X] I have written a descriptive issue title
- [X] I have searched existing issues to ensure the bug has not already been reported

### Fastify version

^4.0.0

### Plugin version

_No response_

### Node.js version

19

### Operating system

Linux

### Operating system version (i.e. 20.04, 11.3, 10)

20.04

### Description

the required for param validation doesn't work and allow empty strings

### Steps to Reproduce

fastify.get<{
Params: {
model: string;
},
Querystring: {
sort: string;
asc: number;
}
}>('/listAll/:model/', {
schema: {
params: {
type: 'object',
properties: {
model: { type: 'string' },
},
required: ['model'],
},
querystring: {
type: 'object',
properties: {
sort: { type: 'string' },
asc: { type: 'number' },
},
required: ['sort'],
},
},
}, async function (request, reply) {
return 'db endpoint for => ' + request.params.model;
});

i undestand this can be fixed with

params: {
type: 'object',
properties: {
model: { type: 'string' },
minLength: 1,
},
required: ['model'],
},

but i think the required on a string should do it for params


### Current Behavior

CURL /listAll/t?sort=p => this is ok

CURL /listAll/t=> validation works , sort is required

CURL /listAll//?sort=p => get ok 200 , validation doesn't works , and allow the model to be empty

### Expected Behavior

CURL /listAll/t?sort=p => this is ok

CURL /listAll/t=> validation works , sort is required

CURL /listAll//?sort=p => validation works , and doesn't allow the model to be empty