Update various strings for IPFS (uplift to 1.19.x)

[brave-builds]

Uplift of #7415
Resolves brave/brave-browser#13169

Approved, please ensure that before merging:

• You have checked CI and the builds, lint, and tests all pass or are not related to your PR.
• You have tested your change on Nightly.
• The PR milestones match the branch they are landing to.

After you merge:

• The associated issue milestone is set to the smallest version that the changes is landed on.

[bbondy]

CI is good to go:

• Windows, macOS, Linux, Android, iOS: audit_deps is failing - not related to these string updates
• Linux: browser-tests failing unrelated to this PR with the test RewardsPublisherBrowserTest.PanelShowsCorrectPublisherData. Looks like a known failure here: "RewardsPublisherBrowserTest.PanelShowsCorrectPublisherData" failing CI intermittently brave-browser#12986
• iOS had a build failure, but not related to this PR since this PR doesn't touch iOS:

[2020-12-13T03:49:56.074Z]       for (const auto& pair : node.DictItems()) {

[2020-12-13T03:49:56.074Z]                        ^

[2020-12-13T03:49:56.074Z] ../../base/json/json_writer.cc:151:12: note: use non-reference type 'std::__1::pair<const std::__1::basic_string<char> &, const base::Value &>'

[2020-12-13T03:49:56.074Z]       for (const auto& pair : node.DictItems()) {

[2020-12-13T03:49:56.074Z]            ^~~~~~~~~~~~~~~~~~

[2020-12-13T03:49:56.074Z] 1 error generated.

[bbondy]

Tested on Nightly and it has the new strings.

[kjozwiak]

Uplift into 1.19.x approved after deliberating with @brave/uplift-approvers.