### Godot version

v4.1.stable.official [970459615]

### System information

Windows 11

### Issue description

Using `String::pad_zeros` on a string containing digits with greater length than the argument `digits` raises the error `Parameter count should be a positive number.` of `String::repeat`, because it is called with a negative parameter.
(Actually this error is not 100% correct, it should be non-negative)

4.0 Code:
https://github.com/godotengine/godot/blob/c8e0bd50c57de91c061866db1de407f2e7a74acd/core/string/ustring.cpp#L4127-L4155

Example: `"2023".pad_zeros(2)`
`begin == 0`
`end == 4`
`end - begin < p_digits == false` => No "0" is inserted, the string is returned unchanged.

4.1 Code:
https://github.com/godotengine/godot/blob/ce5c6151fc498b39fe0c188045a4685e0f627854/core/string/ustring.cpp#L4266-L4290

Example: `"2023".pad_zeros(2)`
`begin == 0`
`end == 4`
`zeros_to_add == 2 - (4 - 0) == -2`
=> `s.insert(0, String("0").repeat(-2))` is called => Error.

I don't know why this was changed, but I think ensuring that `zeros_to_add > 0` should be ensured internally and not by the user. If this condition is not fullfilled the string should be returned unchanged as in the 4.0 implementation.

### Steps to reproduce

Try my above mentioned example in 4.0 and 4.1

### Minimal reproduction project

Not necessary.
const  *s = this;
	if (s->is_empty()) {
		return Vector<uint8_t>();
	}
	Vector<uint8_t> retval;
	size_t len = s->length() * sizeof(char32_t);
	retval.resize(len);
	uint8_t *w = retval.ptrw();
	memcpy(w, (const void *)s->ptr(), len);
	return retval;
}
Vector<uint8_t> ::to_wchar_buffer() const {
#ifdef WINDOWS_ENABLED
	return to_utf16_buffer();
#else
	return to_utf32_buffer();
#endif
}
#ifdef TOOLS_ENABLED
/**
 * "Tools TRanslate". Performs string replacement for internationalization
 * within the editor. A translation context can optionally be specified to
 * disambiguate between identical source strings in translations. When
 * placeholders are desired, use `vformat(TTR("Example: %s"), some_string)`.
 * If a string mentions a quantity (and may therefore need a dynamic plural form),