[Amount Extraction] Add stub implementation for
AmountExtractionHeuristicRegex.

This class will store regex received from Component Updater.

One pager: go/cu_vs_scs

adding the logic

Low-Coverage-Reason: TESTS_IN_SEPARATE_CL Tests will be added when
Bug: 378147177
Change-Id: Ie3ffc2dac19def5c982e33f3ea5eb2a95d3c6302
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6033368
Reviewed-by: Siyu An <siyua@chromium.org>
Reviewed-by: Slobodan Pejic <slobodan@chromium.org>
Commit-Queue: Longsheng Yin <longsheng@google.com>
Cr-Commit-Position: refs/heads/main@{#1386988}