### 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.
}
TEST_CASE("[String] SHA1/SHA256/MD5") {
	String s = "Godot";
	String sha1 = "a1e91f39b9fce6a9998b14bdbe2aa2b39dc2d201";
	static uint8_t sha1_buf[20] = {
		0xA1, 0xE9, 0x1F, 0x39, 0xB9, 0xFC, 0xE6, 0xA9, 0x99, 0x8B, 0x14, 0xBD, 0xBE, 0x2A, 0xA2, 0xB3,
		0x9D, 0xC2, 0xD2, 0x01
	};
	String sha256 = "2a02b2443f7985d89d09001086ae3dcfa6eb0f55c6ef170715d42328e16e6cb8";
	static uint8_t sha256_buf[32] = {
		0x2A, 0x02, 0xB2, 0x44, 0x3F, 0x79, 0x85, 0xD8, 0x9D, 0x09, 0x00, 0x10, 0x86, 0xAE, 0x3D, 0xCF,
		0xA6, 0xEB, 0x0F, 0x55, 0xC6, 0xEF, 0x17, 0x07, 0x15, 0xD4, 0x23, 0x28, 0xE1, 0x6E, 0x6C, 0xB8
	};
	String md5 = "4a336d087aeb0390da10ee2ea7cb87f8";
	static uint8_t md5_buf[16] = {
		0x4A, 0x33, 0x6D, 0x08, 0x7A, 0xEB, 0x03, 0x90, 0xDA, 0x10, 0xEE, 0x2E, 0xA7, 0xCB, 0x87, 0xF8
	};
	PackedByteArray buf = s.sha1_buffer();
	CHECK(memcmp(sha1_buf, buf.ptr(), 20) == 0);
	CHECK(s.sha1_text() == sha1);
	buf = s.sha256_buffer();
	CHECK(memcmp(sha256_buf, buf.ptr(), 32) == 0);
	CHECK(s.sha256_text() == sha256);
	buf = s.md5_buffer();
	CHECK(memcmp(md5_buf, buf.ptr(), 16) == 0);
	CHECK(s.md5_text() == md5);
}
TEST_CASE("[String] Join") {
	String s = ", ";
	Vector<String> parts;