PreTrainedTokenizerFast - whitespace merge skipped 
### System Info

@ArthurZucker 

Most likely I'm wrong, been digging through tokenization for 10 hours in a row and quite new to the topic.
Vocab: https://huggingface.co/tiiuae/falcon-40b/blob/main/tokenizer.json
String: `"Hello  World"`
Two spaces are in the merge list right on top at line 19
" W" is in line 128

Running this through the tokenizer (`tokenizer = PreTrainedTokenizerFast(tokenizer_file='tokenizer.json')`)
Falcon IDs:
`         [9856, 204, 2889]`
Falcon tokens:
`         ['Hello', 'Ġ', 'ĠWorld']`

What I expected:
```
  9856 -> 'Hello'
   258 -> '  ' 
 12670 -> 'World'
```

From my understanding the two whitespaces form a rank 19 merge (the 2nd lowest one next to 'o r' at 12)
I most likely just misunderstand a special rule in BPE in relation to white space characters


### Who can help?

_No response_

### Information

- [ ] The official example scripts
- [ ] My own modified scripts

### Tasks

- [ ] An officially supported task in the `examples` folder (such as GLUE/SQuAD, ...)
- [ ] My own task or dataset (give details below)

### Reproduction

```
import sys
from transformers import PreTrainedTokenizerFast

# Load the tokenizer
tokenizer = PreTrainedTokenizerFast(tokenizer_file='tokenizer.json')

# Define the string to tokenize
text = "Hello  World"

# Check if a command line argument was provided
if len(sys.argv) > 1:
    text = sys.argv[1]

# Tokenize the string
output = tokenizer.encode(text)

# Print the token IDs
print("Falcon IDs:\n\t", output)
tokens = tokenizer.convert_ids_to_tokens(output)
print("Falcon tokens:\n\t", tokens)
```

### Expected behavior

The two spaces form a higher rank than space + W so I'd expect this outcome
  9856 -> 'Hello'
   258 -> '  '
 12670 -> 'World'
The behavior switches to what I expected if you disable pre_tokenizer->use_regex which ignores the rank and contains quite a bit of english grammar rules.
Not sure if that regex snake should really be used by default, given the international use of tokenizers. (ironically TII has chosen it despite being in an arabic speaking country)