Suppress warnings in `modify_ed2in()` about directories on remote server

[Aariq]

pecan/models/ed/R/modify_ed2in.R

Line 219 in f5194f8

ed2in[["FFILOUT"]] <- file.path(normalizePath(output_dir), "analysis")

This line results in a warning that the directory on the HPC doesn't exist, even when it does. I think that was leading me to believe that run.write.configs() was trying to write to the HPC, but it's not.

I think this warning could (and should) be suppressed by changing to normalizePath(output_dir, mustwork = FALSE). Probably all the normalizePath() calls in this function should get mustwork = FALSE

Originally posted by @Aariq in #2992 (comment)