MudTablePager: Add thousands separator for {all_items} variable

[RafBorrelli]

Description

Added thousands separator for the variable {all_items} of MudTablePager

How Has This Been Tested?

none

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• [x] The PR is submitted to the correct branch (dev).
• [x] My code follows the code style of this project.
• [ ] I've added relevant tests.