[Backport queued_ltr_backports] [Processing] Fix Dissolve alg for featureless input layer or containing empty/null geometries, when the output is a memory layer (Fix #53392)

[Backport queued_ltr_backports] [Processing] Fix Dissolve alg for featureless input layer or containing empty/null geometries, when the output is a memory layer (Fix #53392) #5680