Add npm install step to contribution guide in pull request section

[MohamadSalman11]

Prerequisites

• I have searched for duplicate or closed feature requests
• I have read the contributing guidelines

Proposal

It would be nice to include the npm install command in the pull request section of the contribution guide to ensure that all necessary dependencies are installed before starting work on the project.

Motivation and context

Actually, this happened to me often I followed the guide, then tried to run commands like npm run test and got errors. At first, I didn’t understand why, but later figured out that I had forgotten to install the dependencies