Headers with digits are not properly identified when importing

[oleua]

Steps to reproduce

1. Create some table
2. Have a CSV file with columns, which headers contain figures
3. Try to import data from that CSV file
4. In the window with preview observe that the fields which contains digits are not identified.

Expected behavior

Tables with headers containing digits are treated properly.

Actual behavior

Tables with headers containing digits are not properly defined.

Tables app version

No response

Browser

No response

Client operating system

No response

Operating system

No response

Web server

None

PHP engine version

None

Database

None

Additional info