8fdaf2bddc
Caused byee23f0f3fb, which removed the update tag when entering sculpt mode, and byb5f7af31d6, which made these layers lazily created, so they weren't always available at the start of a stroke. Now update the evaluated mesh/multires CCG as necessary. Some updates could potentially avoided when switching modes in the future, but for now do it all the time. Fixes T101116 Also fixes a crash when painting multires mask for the first time