Numbers and delimiters added to a numeric string incorrectly

Problem/motivation:

At its current state, `src/Plugin/Field/FieldFormatter/BigIntItemDefaultFormatter.php` returns incorrect values under certain conditions.

The method numberFormat processes the string as follows:

1. Obtains three characters, starting from the end of a numeric string
2. Stores the obtained characters in the above step in an array
3. Removes the obtained characters from the original numeric string in the variable
4. Repeats 1~3 until the entire string is processed
5. Restores the numeric string from the characters stored in the array, with the specified delimiter

The problem lies in the steps #2 and 3. When the length of the numeric string is either two, or the remainder is 2 when the length is divided by 3, the formatter places the first character and the delimiter at the beginning of the string.

Examples:

• 10 => 110 or 1,10
• 10000 => 110000 or 1,10,000
• 10000000 => 110000000 or 1,10,000,000

Proposed resolution

Apply the patch to correct the formatting issue without making changes to the functionality of the numberFormat method itself.