[OpenAPI 3] Consider remove the constraint that has no impact to the schema

Although the generated document correct, it can be simpler.
e.g.
```
- type: string
minimum: 1
nullable: true
```
`minimum: 1` only applys to number, it's safe to remove it when the type is not number. Should be low priority.

[Playground](https://typespec.io/playground/?c=c2NhbGFyIFN0ciBleHRlbmRzIHN0cmluZzsNCm1vZGVsIE1vbCB7eDrHF30NCsczTnVtyTNpbnQzMjvJG01vcmXJHE51bcoaSW50MTbMNzE2yh1Ob0XGGcwTUm9vdMpMyyINCkBtaW5WYWx1ZSgxKQ0KdW5pb24gdSB7DQrGNizKLyzlAOEsx38s5QC8LOUA2sQGcmUgLCBudWzEDuUAyiAs5wDuDQp9xGnmAQlUZXN0xF4gIM55ICBhOsZyfMpyfMVyfMdyfMVyfMVyxAZyZSB8xnJ8x3J8x3I7DQp9&e=%40typespec%2Fopenapi3&options=%7B%7D)