Update account tiering for SMB Account Executives

Why is this change being made?

• Fixed some typos
• Updated the SMB AE job title from SMB Customer Advocate
• Edited the SMB Account Executive tiering guidelines to be more accurate

Does this MR meet the acceptance criteria?

Assign to DRI

• Did you assign this change to the correct DRI of the page or information you are changing?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what