Errors and deprecations findings

[rikardow]

Hi, thanks for the great work on this plugin

We found some errors and deprecations in the codebase, here's the list

1. File: mod/hvp/reporting/h5p-report.class.php
   Line: 65
   Message: Indirect access to variables, properties and methods will be evaluated strictly in left-to-right order since PHP 7.0. Use curly braces to remove ambiguity.
   Type: error

2. File: mod/hvp/reporting/h5p-report.class.php
   Line: 68
   Message: Indirect access to variables, properties and methods will be evaluated strictly in left-to-right order since PHP 7.0. Use curly braces to remove ambiguity.
   Type: error

3. File: mod/hvp/reporting/h5p-report.class.php
   Line: 93
   Message: Indirect access to variables, properties and methods will be evaluated strictly in left-to-right order since PHP 7.0. Use curly braces to remove ambiguity.
   Type: error

4. File: mod/hvp/editor/h5peditor-ajax.class.php
   Line: 106
   Message: Since PHP 7.0, functions inspecting arguments, like func_get_args(), no longer report the original value as passed to a parameter, but will instead provide the current value. The parameter $endpoint" was usedand possibly changed (by reference)on line 99."
   Type: warning

5. File: mod/hvp/editor/h5peditor-file.class.php
   Line: 14
   Message: The constant \FILTER_SANITIZE_STRING" is deprecated since PHP 8.1"
   Type: warning

Thank you very much for your efforts