clang-tidy error with BaseState.H

[zingale]

When we build with clang-tidy (for example, the flame problem), we get:

Error while processing /home/zingale/development/MAESTROeX/Exec/science/flame/../../../Source/BaseStateGeometry.cpp.
../../../Source/BaseState.H:242:22: error: no member named 'dptr' in 'BaseState<T>' [clang-diagnostic-error]
  242 |         return this->dptr;
      |                ~~~~  ^
Suppressed 40403 warnings (40391 in non-user code, 12 NOLINT).

I think that the issue is that we expect the template class T to have dptr but are not enforcing it.