Adding selector for login shell in account settings

[mckeags7]

No description provided.

[hakasapl]

For the combobox:

<select>
    <option value="" disabled selected hidden>Select Login Shell...</option>
    <option value="hurr">Durr</option>
</select>

For the textbox:

Make it be hidden unless "custom" is selected in the combo box.

<input type=text placeholder="Enter custom login shell...">

[hakasapl]

Some minor syntax fixes and added a suggestion to fix the issue where the textbox doesn't show up on page refresh if the user has a custom shell

[hakasapl]

Thank you!