Update Opt-in description in the Registration Purpose field - External user

[zoeyli-46]

• Registration Purpose description for the opt-in should be: Note: An Opted-in Operation is an industrial operation that produces a regulated product and emits less than 10,000 tCO2e per year. These operations may apply to voluntarily participate in the B.C. OBPS. This option should be selected if your operation has already been designated as an Opted-In Operation, OR if your operation is registering and applying to be an Opted-In Operation for the first time. on the Register Operation - Operation Information page

[zoeyli-46]

@patriciarussellCAS split from #2147