### 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.
parts.push_back("One");
	parts.push_back("B");
	parts.push_back("C");
	String t = s.join(parts);
	CHECK(t == "One, B, C");
}
TEST_CASE("[String] Is_*") {
	static const char *data[12] = { "-30", "100", "10.1", "10,1", "1e2", "1e-2", "1e2e3", "0xAB", "AB", "Test1", "1Test", "Test*1" };
	static bool isnum[12] = { true, true, true, false, false, false, false, false, false, false, false, false };
	static bool isint[12] = { true, true, false, false, false, false, false, false, false, false, false, false };
	static bool ishex[12] = { true, true, false, false, true, false, true, false, true, false, false, false };
	static bool ishex_p[12] = { false, false, false, false, false, false, false, true, false, false, false, false };
	static bool isflt[12] = { true, true, true, false, true, true, false, false, false, false, false, false };
	static bool isid[12] = { false, false, false, false, false, false, false, false, true, true, false, false };
	for (int i = 0; i < 12; i++) {
		String s = String(data[i]);
		CHECK(s.is_numeric() == isnum[i]);
		CHECK(s.is_valid_int() == isint[i]);
		CHECK(s.is_valid_hex_number(false) == ishex[i]);
		CHECK(s.is_valid_hex_number(true) == ishex_p[i]);
		CHECK(s.is_valid_float() == isflt[i]);
		CHECK(s.is_valid_identifier() == isid[i]);
	}
}
TEST_CASE("[String] humanize_size") {
	CHECK(String::humanize_size(1000) == "1000 B");
	CHECK(String::humanize_size(1025) == "1.00 KiB");
	CHECK(String::humanize_size(1025300) == "1001.2 KiB");
	CHECK(String::humanize_size(100523550) == "95.86 MiB");
	CHECK(String::humanize_size(5345555000) == "4.97 GiB");