add custom parameter to the language tracker

[RamyAlshurafa]

Issues this PR relates to

270

followed this tutorial https://www.youtube.com/watch?v=AaCnaI_tqes and created this report https://analytics.google.com/analytics/web/?authuser=2#/analysis/p343721545/edit/Z4KwtlxjRKyO11BRrdOdIA (it will take 24-48 hours to start collecting data)

and added language chart here https://analytics.google.com/analytics/web/?authuser=2#/p343721545/reports/dashboard/edit?params=_u..nav%3Dmaui%26_r.7..selmet%3D%5B%22activeUsers%22%5D&r=5839908824&collectionId=life-cycle

https://analytics.google.com/analytics/web/?authuser=2#/analysis/p343721545/edit/Z4KwtlxjRKyO11BRrdOdIA

NOTE: REMEMBER NOT TO REVIEW UNLESS ALL ACCEPTANCE CRITERIA HAS BEEN TICKED OFF

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Any info the reviewer needs to know to test

e.g. Add env vars, run npm install

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Any info the team needs to consider before merged into development

e.g. Will a database need to be rebuilt (and is this ok if existing data), add env vars

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