correct label for "Principal Investigator (PI)" on "Find your project" page

[magicalmary]

When adding an existing dmp using the "Upload Plan" feature on staging instance:

Wrong word for 'principal' is used in the field label for PI in the "Find your project" screen. Please change "Principle Investigator (PI)" to "Principal Investigator (PI)" (see screenshot).

(Bolding above added for emphasis; do not bold the word on the webpage.)

[magicalmary]

Testing success!