Bug/augmentation output differs from input file

[ArshaanNazir]

Description

This PR fixes augmentation and also for swap_entities ( takes care of sentences having I-labels only without the B-tag)

We fixed an issue in the data augmentation process where augmented files format differed from input files, leading to inconsistencies that was negatively impacting model training and evaluation.

Expected Output

-DOCSTART- -X- -X- O

CRICKET NNP B-NP O
- : O O
LEICESTERSHIRE NNP B-NP B-ORG
TAKE NNP I-NP O
OVER IN B-PP O
AT NNP B-NP O
TOP NNP I-NP O
AFTER NNP I-NP O
INNINGS NNP I-NP O
VICTORY NN I-NP O
. . O O

Actual Output

-DOCSTART- -X- -X- O

CRICKET -X- -X- O
- -X- -X- O
LEICESTERSHIRE -X- -X- B-ORG
TAKE -X- -X- O
OVER -X- -X- O
AT -X- -X- O
TOP -X- -X- O
AFTER -X- -X-O
INNINGS -X- -X- O
VICTORY -X- -X- O
. -X- -X- O

Swap-entities issue:

[chakravarthik27]

LGTM