Merge branch '580-passive-tracers-dta-files-reading-bug' into 'branch_5.0'

Resolve "passive tracers dta files reading bug"

Closes #580 (closed)

See merge request !776 (merged)

(cherry picked from commit 5f59df37)

48d6d675 fix fld_read issue + pass tracer index as argument (instead of tracer id) d4729ea7 fix indexes

Co-authored-by: Guillaume Samson