### 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.
CHECK(l.size() == 4);
	for (int i = 0; i < l.size(); i++) {
		CHECK(l[i] == slices_3[i]);
	}
	s = "";
	l = s.split();
	CHECK(l.size() == 1);
	CHECK(l[0] == "");
	l = s.split("", false);
	CHECK(l.size() == 0);
	s = "Mars Jupiter Saturn Uranus";
	const char *slices_s[4] = { "Mars", "Jupiter", "Saturn", "Uranus" };
	l = s.split_spaces();
	for (int i = 0; i < l.size(); i++) {
		CHECK(l[i] == slices_s[i]);
	}
	s = "1.2;2.3 4.5";
	const double slices_d[3] = { 1.2, 2.3, 4.5 };
	Vector<double> d_arr;
	d_arr = s.split_floats(";");
	CHECK(d_arr.size() == 2);
	for (int i = 0; i < d_arr.size(); i++) {
		CHECK(ABS(d_arr[i] - slices_d[i]) <= 0.00001);
	}
	Vector<String> keys;
	keys.push_back(";");
	keys.push_back(" ");
	Vector<float> f_arr;
	f_arr = s.split_floats_mk(keys);
	CHECK(f_arr.size() == 3);