A tooltip is always prepared, even if item value is an empty string or consists of several spaces.

Steps to reproduce:
Case 1:

1. Create a trapper item with type of information "Character" or "Text".
2. Send an empty string to the trapper item.
3. Navigate to Latest data.
4. Observed: The last value of the trapper item is empty.
5. Right-click on the cell with item value and select "Inspect element".
6. Observed:

   <td>
       <span class="cursor-pointer" data-hintbox="1" data-hintbox-static="1" data-hintbox-delay="0"></span>
       <div class="hint-box" style="display: none;"><div class="hintbox-wrap"></div></div>
   </td>
   

Case 2:

1. Send a string with multiple spaces to the trapper item.
2. Observed: The browser displays extra spaces as one and the result is very similar to the Case 1.

Case 3:

1. Create a host with value mapping <empty string> => Empty string.
2. Create a trapper item with type of information "Character" on this host.
3. Send an empty string to the trapper item.
4. Navigate to Latest data.
5. Observed: The last value is "Empty string ()". An empty tooltip is displayed when the cursor is hovered over the item value.
6. Create an Item value widget for this item.
7. Observed: The last value is "Empty string ()".

Expected:
1. Item value should always be trimmed for both last value and tooltip. There is no need to rely on the browser to do this.
2. If trimming results in an empty string, the latter should be displayed using a special word, for example, Empty. Tooltip should not be displayed for such values.