Add iOS metric for primary language

[DJAndries]

Please replicate https://github.com/brave/brave-browser/issues/34853.

[AndyAnds265]

@iccub I just wanted to check on the status of this. Getting language data on iOS is a high priority for growth as we are monitoring changes in Search and Browser since the European choice screens were released.

[chrismore]

@DJAndries Hey Darnell. What is the level of effort for this one?

[iccub]

We can get it in this week. I do not think we have prioritized it highly

[DJAndries]

@chrismore Should be a relatively short task

[chrismore]

If it is low effort, we might as well knock it out so we have parity across platforms with the insights.

Is this in the P3A pod or iOS general pod?

[iccub]

@chrismore do you have any preference what release version do you want to have this in?

[chrismore]

@chrismore do you have any preference what release version do you want to have this in?

Sooner the better :-)

[GeetaSarvadnya]

Verification PASSED on iPhone 8 version 16.7.8 running Brave Nightly 1.68(79)

• Verified few languages by comparing the actual langcodes matching with response value and browser language.

English:

langcodes	local state	device language	device region

Germany:

langcodes	local state	device language	device region

France:

langcodes	local state	device language	device region

Kannada:

langcodes	local state	device language	device region