Implement parsing of the Amount from the Transaction ID

[yyosifov]

• For EUR transactions - try parsing the amount from the Transaction Id
• Added unit tests for the regex and the prepare transaction functions

Closes #1462 (from the frontend repo)

[github-actions]

✅ Tests will run for this PR. Once they succeed it can be merged.

[igoychev]

Amazing job with the tests and the corner cases!!!
Please see my two comments regarding !=BGN and additional safety with marking the transaction as unrecognized if parsing didn't work.

[sashko9807]

Assuming that the position of the amount is the exact same on every transactionId, and the amount is always represented as a decimal number, can't we just use transactionId.slice(-16, -9). Should be faster than doing regex matching on the string.

[igoychev]

Great and special thanks again for the extra safety!

[igoychev]

Wow! Great example for setting the high bar of how test data should look like!

[yyosifov]

@sashko9807 Sorry, I just saw your comment. Here are my thoughts:

• Regarding performance - I doubt it will be a big difference for so short string and the operation is quite rare - i.e. only happens on a new transaction. I would agree that we should improve readability/maintainability if there is a way :)
• The slice you suggested looks cool, but it will work only if we have 7 symbols in the Amount. For example, if someone donated 100 EUR it won't parse it correctly. Example: 'Booked_6516347588_70001524349032963FTRO23184809601C20230703100.00_20230703'.slice(-16, -9)' = '3100.00' which is incorrect