Custom invoice colour without hash sign is not interpreted on invoice

[vitis586]

Akaunting version

3.1.5

PHP version

Cloud Trial

Operating system

Cloud Trial

Steps to reproduce

1. Create an invoice
2. Download invoice - example with colour purple-900
   inv-00001-1703874729.pdf
3. Go to Settings - Invoice and change colour to #662581 - the circle changes colour
4. Download invoice
   inv-00001-1703876280.pdf
5. Go to Settings - Invoice and change colour to 662581 - the circle changes colour again, so the colour gets interpreted correctly
6. Download invoice
   inv-00001-1703876583.pdf

Expected result

There should be either an error when the colour does not have the hash sign or the colour should not be interpreted at all

Actual result

The colour code without the hash sign gets interpreted in the settings but not in the generated PDF invoice

Additional comments

No response

Relevant log output

No response