Remove GraphQL Conf banner

[forivall]

Description

Remove the banner since GraphQL Conf 2024 is in the past

Related PR : #2486

Type of change

Please delete options that are not relevant.

• documentation only change

Screenshots/Sandbox (if appropriate/relevant):

documentation only change

How Has This Been Tested?

documentation only change

Test Environment:

N/A: documentation only change

• OS:
• GraphQL Scalars Version:
• NodeJS:

Checklist:

N/A: documentation only change

• I have followed the
  CONTRIBUTING doc and the
  style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests and linter rules pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

Further comments

documentation only change