User input validation to avoid data manipulation

User input validation: Strictly compares to boolean _false_.

This vulnerability affects the following application versions:

• Contact Form 7 3.6
• Contact Form 7 3.7
• Contact Form 7 3.7.1
• Contact Form 7 3.7.2
• Contact Form 7 3.8
• Contact Form 7 3.8.1
• Contact Form 7 3.9
• Contact Form 7 3.9.1
• Contact Form 7 3.9.2
• Contact Form 7 3.9.3
• Contact Form 7 3.9-beta
• Contact Form 7 4.0
• Contact Form 7 4.0.1
• Contact Form 7 4.0.2
• Contact Form 7 4.0.3
• Contact Form 7 4.1
• Contact Form 7 4.1.1
• Contact Form 7 4.1.2
• Contact Form 7 4.1-beta
• Contact Form 7 4.2
• Contact Form 7 4.2.1
• Contact Form 7 4.2.2
• Contact Form 7 4.2-beta
• Contact Form 7 4.3
• Contact Form 7 4.3.1
• Contact Form 7 4.4
• Contact Form 7 4.4.1
• Contact Form 7 4.4.2
• Contact Form 7 4.5
• Contact Form 7 4.5.1
• Contact Form 7 4.6
• Contact Form 7 4.6.1
• Contact Form 7 4.7
• Contact Form 7 4.8
• Contact Form 7 4.8.1
• Contact Form 7 4.9
• Contact Form 7 4.9.1
• Contact Form 7 4.9.2
• Contact Form 7 5.0
• Contact Form 7 5.0.1
• Contact Form 7 5.0.2
• Contact Form 7 5.0.3
• Contact Form 7 5.0.4
• Contact Form 7 5.0.5
• Contact Form 7 5.1
• Contact Form 7 5.1.1
• Contact Form 7 5.1.2
• Contact Form 7 5.1.3
• Contact Form 7 5.1.4
• Contact Form 7 5.1.5
• Contact Form 7 5.1.6
• Contact Form 7 5.1.7
• Contact Form 7 5.1.8