Pass \WebDriver\Element always as an object for execute

[mvorisek]

and fix Selenium v4.x support as it does not support legacy ELEMENT key.

[codecov]

Codecov Report

Merging #353 (4ee4eca) into master (e5f8421) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##             master     #353   +/-   ##
=========================================
  Coverage     90.02%   90.02%           
  Complexity      150      150           
=========================================
  Files             1        1           
  Lines           421      421           
=========================================
  Hits            379      379           
  Misses           42       42           

Impacted Files	Coverage Δ
src/Selenium2Driver.php	90.02% <100.00%> (ø)

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[aik099]

1. what are the benefits (or fixes) provided by this change?
2. are all tests still pass?

[mvorisek]

what are the benefits (or fixes) provided by this change?

see instaclick/php-webdriver#80, instaclick/php-webdriver@b5b18bd and spec https://w3c.github.io/webdriver/#executing-script

ELEMENT key is Selenium 2.x serialization, for Selenium 3.x it is still supported, but W3C element-6066-11e4-a52e-4f735466cecf key is recommended

for Selenium 4.x, only the later is supported

the serialization, since v1.4.14, is natively supported in instaclick/php-webdriver so this PR simplifies the code in this repo and leaves the serialization logic to the underlaying driver

2. are all tests still pass?

yes, no BC break

[aik099]

Merging. Thanks @mvorisek .

[aik099]

Turns out, that without this fix attempt to use the NodeElement::getAttribute method will fail on the BrowserStack.