fix: base64 options doesn't apply

[aseyfpour]

Description

By passing { urlSafe: true } to @IsBase64, it is supposed to validate base64url correctly, but it doesn’t seem to work properly.

Minimal code-snippet showcasing the problem

export class Base64Test {
  @IsBase64({ urlSafe: true })
  base64: string;

  static from(base64: string): Base64Test {
    return plainToInstance(Base64Test, { base64 });
  }
}

const obj = Base64Test.from("dGVzdA");
const errors = await validate(obj);

if (errors.length > 0) {
  console.log("Failed to validate")
} else {
  console.log("Successfully validated")
}

Expected behavior

It should log Successfully validated

Actual behavior

It logs Failed to validate