Add to Sidebar widget is missing its tooltip

[stephendonner]

Description

Add to Sidebar widget is missing its tooltip

Steps to Reproduce

1. new profile
2. load brave://flags/#sidebar and enable the sidebar
3. restart Brave
4. hover over the ➕ icon/widget on the bottom of the sidebar

Actual result:

There's no tooltip on hover

Expected result:

Like the other icons/widgets (Brave Together, Crypto Wallets, Bookmarks, History, Experiments) there should probably be a tooltip on hover, for the Add to Sidebar widget/icon

Reproduces how often:

100%

Brave version (brave://version info)

Brave	1.25.33 Chromium: 90.0.4430.85 (Official Build) nightly (x86_64)
Revision	5bc145d831c180d9ff94f29a0d7a2e1cbd30ef36-refs/branch-heads/4430@{#1311}
OS	macOS Version 11.2.3 (Build 20D91)

[simonhong]

When hovered, we will show add item menu bubble instead of tooltip by brave/brave-core#8769.

[stephendonner]

Verified FIXED using

Brave	1.26.18 Chromium: 91.0.4472.38 (Official Build) nightly (64-bit)
Revision	8155e7afab5d695cf0e028f4d77203287523cda9-refs/branch-heads/4472_35@{#6}
OS	Windows 10 OS Version 2009 (Build 21376.1)

Steps:

1. new profile
2. load brave://flags/#sidebar and enable the sidebar
3. restart Brave
4. hover over the ➕ icon/widget on the bottom of the sidebar

Confirmed I got a menu bubble Add to Sidebar with the current tab's site URL available to add to the sidebar