When adding a site search engine, the first text field in the popup should receive focus

[wknapik]

Description

When this window pops up at brave://settings/searchEngines

the cursor is not in the first text field, requiring an extra click, or tab

Steps to Reproduce

1. Go to brave://settings/searchEngines
2. Click on Add to the right of Site search
3. A windows pops up with 3 text fields, but none are focused, requiring an extra click, or tab

Actual result:

No focus in first text field

Expected result:

Focus in first text field

Reproduces how often:

Easily reproduced

Brave version (brave://version info)

Brave 1.65.133 Chromium: 124.0.6367.208 (Official Build) (64-bit)
Revision a719189e6a0245a6ce7fab3ddc637e8bd75aed08
OS Linux

Version/Channel Information:

• Can you reproduce this issue with the current release? Yes
• Can you reproduce this issue with the beta channel? Yes
• Can you reproduce this issue with the nightly channel? Yes

Other Additional Information:

• Does the issue resolve itself when disabling Brave Shields? n/a
• Does the issue resolve itself when disabling Brave Rewards? n/a
• Is the issue reproducible on the latest version of Chrome? n/a

Miscellaneous Information: