[REF-2626] reflex init generates incorrect reflex version in requirements.txt

[camstuart]

Describe the bug
When generating a brand new reflex project with init the incorrect reflex version is added to the generated requirements.txt file

To Reproduce

python -m venv .venv
source .venv/bin/activate
pip install reflex
reflex init
cat requirements.txt # reflex==0.4.5
reflex -v # 0.4.8.post1

Expected behavior
The output of reflex -v should match the version specified in requirements.txt

Specifics (please complete the following information):

• Python Version: 3.12.2 (via pyenv)
• PIP Version: 24.0
• Reflex Version: 0.4.8.post1
• OS: Mac 14.4.1
• Browser (Optional): N/A

_REF-2626