Reactions should not use strict implicit valence calculations

[mwojcikowski]

Configuration:

• RDKit Version: 2020.09 (present in 2019.09+)
• Operating system: MacOS

Description:
RunReactants should just apply the transformation and return unsanitized mols, instead it is forcing calculation of explicit valence in strict mode, thus producing error. This is a regression that happened somewhere after 2019.03 release.

Expected behavior:
The reaction should not fail in such way, even with messed up (but still valid) SMARTS.

Example
I understand that the SMARTS is not ideal, although that is the minimal example that triggers the error.

rxn = AllChem.ReactionFromSmarts('[c:6][n:7][c:8].[N:14]#[N:15]>>[C:6].[C:8][N:7]=[N+:14]=[N-:15]')                                                                                                                                                              
rxn.RunReactants((Chem.MolFromSmiles('c1cc[nH]c1'), Chem.MolFromSmiles('N#N')))                                                                                                                                                                                  

Error: [14:57:42] Explicit valence for atom # 1 N, 4, is greater than permitted

[mwojcikowski]

I believe these are the offending lines. PR coming soon.