Fix bad quotes in SMTP header.

[osma]

Fixes #936

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!

0 Bugs
0 Vulnerabilities (and 0 Security Hotspots to review)
0 Code Smells

No Coverage information
0.0% Duplication

[codecov]

Codecov Report

Merging #939 into master will not change coverage.
The diff coverage is 0%.

@@            Coverage Diff            @@
##             master     #939   +/-   ##
=========================================
  Coverage     58.27%   58.27%           
  Complexity     1490     1490           
=========================================
  Files            32       32           
  Lines          4168     4168           
=========================================
  Hits           2429     2429           
  Misses         1739     1739

Impacted Files	Coverage Δ	Complexity Δ
controller/WebController.php	17.75% <0%> (ø)	95 <0> (ø)	⬇️

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