For #16317: resets long press delay at the end of UI tests

[sv-ohorvath]

As requested in #16317, this resets the long tap delay set before launching the activity in UI tests.

Pull Request checklist

• Tests: This PR includes thorough tests or an explanation of why it does not
• Screenshots: This PR includes screenshots or GIFs of the changes made or an explanation of why it does not
• Accessibility: The code in this PR follows accessibility best practices or does not include any user facing features. In addition, it includes a screenshot of a successful accessibility scan to ensure no new defects are added to the product.

To download an APK when reviewing a PR:

1. click on Show All Checks,
2. click Details next to "Taskcluster (pull_request)" after it appears and then finishes with a green checkmark,
3. click on the "Fenix - assemble" task, then click "Run Artifacts".
4. the APK links should be on the left side of the screen, named for each CPU architecture

[sv-ohorvath]

400 ms is the default value for "Short"

[codecov-io]

Codecov Report

Merging #18029 (9578897) into master (dfc5628) will increase coverage by 0.13%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##             master   #18029      +/-   ##
============================================
+ Coverage     32.83%   32.97%   +0.13%     
- Complexity     1382     1383       +1     
============================================
  Files           461      461              
  Lines         19425    19425              
  Branches       2712     2712              
============================================
+ Hits           6379     6406      +27     
+ Misses        12510    12486      -24     
+ Partials        536      533       -3     

Impacted Files	Coverage Δ	Complexity Δ
...components/toolbar/BrowserToolbarMenuController.kt	72.67% <0.00%> (+10.92%)	0.00% <0.00%> (ø%)
...java/org/mozilla/fenix/perf/PerformanceInflater.kt	95.00% <0.00%> (+15.00%)	5.00% <0.00%> (+1.00%)
...rg/mozilla/fenix/components/toolbar/ToolbarMenu.kt	86.95% <0.00%> (+17.39%)	0.00% <0.00%> (ø%)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update dfc5628...9578897. Read the comment docs.

[mcarare]

LGTM!