enable yearly timesteps for xlsx exprt

[orichters]

Purpose of this PR

• in fix bug in RIKEN config, let 45/none set carbonprices to 0 only for t, not ttot #2056, I set the usual export scripts such that only normal REMIND timesteps are exported, but forgot to undo it for scenarioMIP

Type of change

• Bug fix

Checklist:

• My code follows the coding etiquette
• I performed a self-review of my own code
• I explained my changes within the PR, particularly in hard-to-understand areas
• All automated model tests pass, executed after my final commit (FAIL 0 in the output of make test). I ran multiple exports and it works

[laurinks]

Thanks @orichters for spotting and correcting! :)