Fall back to TLA+ definition if Java module override of `SequencesExt!ReplaceFirstSubSeq` cannot load Apache Commons Lang3 StringUtils class. (Not done for `ReplaceAllSubSeqs` because the TLA+ def fails because it involves `DOMAIN str` that TLC doesn't handle) Related to Github PR #59 https://github.com/tlaplus/CommunityModules/pull/59/ [Refactor] Signed-off-by: Markus Alexander Kuppe <[email protected]>