[BUG] parsing a string containing escaped double quotes during polymorphic deserialization

### Problem Description

* Parsing a string containing escaped double quotes throws exception during polymorphic deserialization if the string comes before a field defining the object's type.

### Environment Information

- JDK: Eclipse Temurin 25.0.1
- Version Information: Fastjson2 2.0.61

### Reproduction Steps
Example code:
```java
@JSONType(typeKey = "objectType")
sealed interface Animal {
@JSONType(typeName = "cat")
record Cat(String field) implements Animal {
}
}

String json = "{\"field\": \"some\\\"text\", \"objectType\": \"cat\"}";
// Actual JSON to parse: {"field": "some\"text", "objectType": "cat"}
JSON.parseObject(json, Animal.class); // throws com.alibaba.fastjson2.JSONException
```

Output:
```
com.alibaba.fastjson2.JSONException: illegal fieldName input116, offset 18, character t, line 1, column 18, fastjson-version 2.0.61 {"field": "some\"text", "objectType": "cat"}

at com.alibaba.fastjson2.JSONReader.readFieldNameHashCodeError(JSONReader.java:6885)
at com.alibaba.fastjson2.JSONReaderASCII.readFieldNameHashCode(JSONReaderASCII.java:129)
at com.alibaba.fastjson2.reader.ObjectReaderNoneDefaultConstructor.readObject(ObjectReaderNoneDefaultConstructor.java:310)
at com.alibaba.fastjson2.reader.ORG_1_1_Cat.readObject(Unknown Source)
at com.alibaba.fastjson2.reader.ObjectReaderSeeAlso.readObject(ObjectReaderSeeAlso.java:312)
at com.alibaba.fastjson2.JSON.parseObject(JSON.java:992)
```

### Expected Correct Result
String in the field must be deserialized correctly as: `some"text`

Start with JSON.parseObject and follow the stack trace through JSONReaderASCII.readFieldNameHashCode, ObjectReaderNoneDefaultConstructor.readObject, and ObjectReaderSeeAlso.readObject. Reproduce the sealed Animal example with the escaped quote before objectType, then verify that polymorphic deserialization returns the Cat with field equal to some\"text instead of throwing JSONException.

Written by the indexing model from the issue text.