Is it safe to drink raw honey while pregnant for sinus infections?

Safe, not effective. Honey is not recommended for children under 1 year old because their digestive systems cannot eliminate the toxin that can causes infant botulism. "pasteurization" of honey is designed to prevent crystallization, not eliminate the toxin, so infants should not eat any honey. Mothers can safely eat honey, although there are more effective ways to treat sinsusitis.
Potential risk. If you have been diagnosed with an acute sinus infection, and are pregnant your provider with your obstetrician's input, will recommend the appropriate medications to use. Most ob/gyn's would recommend that you not drink raw, "unpasteurized" honey or other unpasteurized product. This would include milk and cheese.