### 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(String::num(-10000.0000012345432123454321) == "-10000.0000012345");
	CHECK(String::num(0.0000000000012345432123454321) == "0.00000000000123");
	CHECK(String::num(0.0000000000012345432123454321, 3) == "0");
	
	
	CHECK(String::num(0.0000056789876567898765) == "0.00000567898766"); 
	CHECK(String::num(10000.000005678999999999) == "10000.000005679"); 
	CHECK(String::num(42.12999999, 6) == "42.13"); 
	
	
	CHECK(String::num(0.00000123456789987654321123456789987654321, 32).length() == 34);
	CHECK(String::num(0.00000123456789987654321123456789987654321, 42).length() == 34); 
	CHECK(String::num(10000.00000123456789987654321123456789987654321, 42).length() == 38); 
}
TEST_CASE("[String] String to integer") {
	static const char *nums[4] = { "1237461283", "- 22", "0", " - 1123412" };
	static const int num[4] = { 1237461283, -22, 0, -1123412 };
	for (int i = 0; i < 4; i++) {
		CHECK(String(nums[i]).to_int() == num[i]);
	}
}
TEST_CASE("[String] Hex to integer") {
	static const char *nums[4] = { "0xFFAE", "22", "0", "AADDAD" };
	static const int64_t num[4] = { 0xFFAE, 0x22, 0, 0xAADDAD };
	for (int i = 0; i < 4; i++) {
		CHECK(String(nums[i]).hex_to_int() == num[i]);
	}
}
TEST_CASE("[String] String to float") {
	static const char *nums[4] = { "-12348298412.2", "0.05", "2.0002", " -0.0001" };