fix: Fix session proposal email link

[mrsaicharan1]

Fixes #5976

Checklist

• I have read the Contribution & Best practices Guide and my PR follows them.
• My branch is up-to-date with the Upstream development branch.
• The unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

• All the functions created/modified in this PR contain relevant docstrings.

Short description of what this resolves:

There is an extra leading slash present which gives a wrong url link to the new session proposal.
This fix removes the leading slash for it.

Changes proposed in this pull request:

• Fixes the buggy link for sessions proposal.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (development@386ecc6). Click here to learn what that means.
The diff coverage is 50%.

@@              Coverage Diff               @@
##             development    #6010   +/-   ##
==============================================
  Coverage               ?   66.26%           
==============================================
  Files                  ?      285           
  Lines                  ?    14005           
  Branches               ?        0           
==============================================
  Hits                   ?     9280           
  Misses                 ?     4725           
  Partials               ?        0

Impacted Files	Coverage Δ
app/api/sessions.py	41.66% <50%> (ø)

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[shreyanshdwivedi]

@mrsaicharan1 are we going to update the frontend url in this PR too?
If not, this PR LGTM

[iamareebjamal]

Please use make_frontend_url. It handles all these edge cases

[mrsaicharan1]

Yes, will do that.

…

On Sat, 8 Jun 2019 at 10:50 AM, Areeb Jamal ***@***.***> wrote: Please use make_frontend_url. It handles all these edge cases — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#6010?email_source=notifications&email_token=AGAHUW3OG4KA6VFTA6M7XWTPZPIL3A5CNFSM4HVZV5B2YY3PNVWWK3TUL52HS4DFVREXG43VMVBW63LNMVXHJKTDN5WW2ZLOORPWSZGODXHXEOA#issuecomment-500134456>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AGAHUW5HVYDTXGXKK32GZRTPZPIL3ANCNFSM4HVZV5BQ> .

[mrsaicharan1]

@uds5501 @shreyanshdwivedi Please review

[kushthedude]

Looks Good