TypeAdapterFactory INTEGER_FACTORY will change INTEGER type to LONG type

# Gson version
2.10.1

# Java / Android version
21

# Description
I try to get a JsonElement by toJsonTree method. but i found that when i use integer object as input, i will get a long object with method ```JsonElement.getAsNumber()```

I think this commit caused this problem：https://github.com/google/gson/commit/3e3266cf48f132928225e1561a6ae4cb5503d08f

Is this a bug or a feature?

## Expected behavior
use integer type as input, get integer type as output

## Actual behavior
use integer type as input, get long type as output

# Reproduction steps
```
@Test
public void test(){
Integer testNum = 1;
JsonElement jsonTree = new Gson().toJsonTree(testNum);
System.out.println(jsonTree.getAsNumber().getClass());
}
```