### 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.
if (len == 0) {
		return 0;
	}
	const char32_t *s = ptr();
	int64_t sign = s[0] == '-' ? -1 : 1;
	if (sign < 0) {
		s++;
	}
	if (len > 2 && s[0] == '0' && lower_case(s[1]) == 'b') {
		s += 2;
	}
	int64_t binary = 0;
	while (*s) {
		char32_t c = lower_case(*s);
		int64_t n;
		if (c == '0' || c == '1') {
			n = c - '0';
		} else {
			return 0;
		}
		// 
		bool overflow = ((binary > INT64_MAX / 2) && (sign == 1 || (sign == -1 && binary != (INT64_MAX >> 1) + 1))) || (sign == -1 && binary == (INT64_MAX >> 1) + 1 && c > '0');
		ERR_FAIL_COND_V_MSG(overflow, sign == 1 ? INT64_MAX : INT64_MIN, "Cannot represent " + *this + " as a 64-bit signed integer, since the value is " + (sign == 1 ? "too large." : "too small."));
		binary *= 2;
		binary += n;
		s++;
	}
	return binary * sign;
}
int64_t ::to_int() const {