wrong screenshot in tb cs docs

[iambodo]

@YuryRog
The screenshot for TB registration stage shows the enrollment page, not the first stage.

https://github.com/dhis2/metadata-package-development/blob/master/metadata/TB_Tracker/TB-REG_TRACKER_V1_DHIS2.33/tb_case_surveillance_design.md#stage-1-tb-registration