Gamma Value can't be increased above 1.0

Earlier Before Render dragon rendering engine was introduced we could use Full bright texture packs which gave us ability to increase the viewing capability in dark areas but after render dragon was introduced shaders are no longer supported.
Also in Java edition players can change Gamma Value above 1.0 to get full bright effect but in bedrock edition gamma Value resets to 1.0 every time the game is opened.

Steps to Reproduce :
Note- You need to set storage to External for this.
Go to a file manager and open the following directory : Android>data>com.mojang.minecraftpe>files>games>com.mojang>minecraftpe>options.txt

In this options.txt file find a value called gfx_gamma
Change it's value from 1.0 to any higher value
Open Minecraft
Reopen options.txt file and observe

Observed Results
The gamma Value gets reset to 1.0

Expected Results (vanilla_parity)
The gamma Value stays to what you entered previously and in your minecraft worlds everything is light up like night vision potion.