Deprecated null parameter in parse_str() and strtr()

Problem/Motivation

Deprecated function: parse_str(): Passing null to parameter #1 ($string) of type string is deprecated in views_field_tooltip__get_tooltip_url() (line 699 of views_field_tooltip/views_field_tooltip.module).
Deprecated function: strtr(): Passing null to parameter #1 ($string) of type string is deprecated in views_field_tooltip__inject_tooltip() (line 549 of views_field_tooltip/views_field_tooltip.module).

Steps to reproduce

Proposed resolution

Check the variable before using it in those functions.

Remaining tasks

User interface changes

API changes

Data model changes