[BUG] change messages shows up as \u2013 for some rows in email alert CSV

[Samyak2]

Describe the bug

When an individual alert email is received, it includes a CSV of the data. The change_message column has the value \u2013 for a few rows. \u2013 is the unicode value for en-dash (– <- this character). This character was used instead of a plain hyphen because it looks better when used in isolation (this change was introduced in bca67f9).

Explain the environment

• Chaos Genius version: v0.5.0 and above
• OS Version / Instance: all
• Deployment type: all

Steps to reproduce

• Setup a KPI which has changes from 0 to 0 for the latest date
• Setup an email alert for this KPI
• Configure anomaly for the KPI
• Open the CSV sent along with email alert
• Notice \u2013 in some rows in the change_message column