[Feature] Text Formula LEFTB

[sagarwal3005]

Initial checklist

• [X] Is this really a problem?
• [X] I have searched the Github Issues for similar issues, but did not find anything.

Problem

Formula LEFTB is not implemented

Solution

Implement formula LEFTB Reference https://support.microsoft.com/en-us/office/left-leftb-functions-9203d2d2-7960-479b-84c6-1ea52b99640c @sagarwal3005 : I can solve it