### 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.
static const bool abs[8] = { true, true, false, false, true, true, true, true };
	for (int i = 0; i < 8; i++) {
		CHECK(String(path[i]).get_base_dir() == base_dir[i]);
		CHECK(String(path[i]).get_basename() == base_name[i]);
		CHECK(String(path[i]).get_extension() == ext[i]);
		CHECK(String(path[i]).get_file() == file[i]);
		CHECK(String(path[i]).is_absolute_path() == abs[i]);
		CHECK(String(path[i]).is_relative_path() != abs[i]);
		CHECK(String(path[i]).simplify_path() == String(simplified[i]));
		CHECK(String(path[i]).simplify_path().get_base_dir().path_join(file[i]) == String(path[i]).simplify_path());
	}
	static const char *file_name[3] = { "test.tscn", "test://.xscn", "?tes*t.scn" };
	static const bool valid[3] = { true, false, false };
	for (int i = 0; i < 3; i++) {
		CHECK(String(file_name[i]).is_valid_filename() == valid[i]);
	}
}
TEST_CASE("[String] hash") {
	String a = "Test";
	String b = "Test";
	String c = "West";
	CHECK(a.hash() == b.hash());
	CHECK(a.hash() != c.hash());
	CHECK(a.hash64() == b.hash64());
	CHECK(a.hash64() != c.hash64());
}
TEST_CASE("[String] uri_encode/unescape") {
	String s = "Godot Engine:'docs'";
	String t = "Godot%20Engine%3A%27docs%27";
	String x1 = "T%C4%93%C5%A1t";