GitLab

Before:
We had PaymentRequestOptionalTotal flag in runtime-enabled flag,
base-feature in components/, base-feature in content/.

After:
We don't have PaymentRequestOptionalTotal anymore. The original
PaymentRequestOptionalTotal flag callers call the DigitalGood flag
instead.

Change:
* Remove unnecessary OptionalTotal flag. Since the CL[1] introduced the
PaymentRequestOptionalTotal flag in unnecessary places, this CL removes
those unnecessary occurrences.
* Merge the PaymentRequestOptionalTotal flag to DigitalGoods flag

[1] https://chromium-review.googlesource.com/c/chromium/src/+/2150974

Bug: 1066531

Change-Id: I67ac986442f805bbac156e45cb3353edf658c245
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2222909Reviewed-by: Rouslan Solomakhin <rouslan@chromium.org>
Reviewed-by: Yaron Friedman <yfriedman@chromium.org>
Reviewed-by: Liquan (Max) Gu <maxlg@chromium.org>
Commit-Queue: Liquan (Max) Gu <maxlg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#774948}