chore(lint): Fix warnings when running linter

- closes: #6125

Changes:

- drop `gomnd` as it has been replaced by `mnd` (see golangci/golangci-lint#4572) and then removed (see golangci/golangci-lint#5110)
  - addresses warning: `WARN [lintersdb] The linter "gomnd" is deprecated (step 2) and deactivated. It should be removed
   from the list of disabled linters. https://golangci-lint.run/product/roadmap/#linter-deprecation-cycle`
- disable `tenv` as the same functionality is provided by `usetesting` and we enable it with `enable-all: true`
  - addresses warning: `WARN The linter 'tenv' is deprecated (since v1.64.0) due to: Duplicate feature
  another linter. Replaced by usetesting.`

Author: michalvavrik

.golangci.yml

@@ -98,7 +98,6 @@ linters:
     - gocyclo
     - godox
     - err113
-    - gomnd
     - ireturn
     - nilnil
     - nlreturn
@@ -112,3 +111,4 @@ linters:
     # TODO: too much work at this stage as many files are impacted by the lint suggestions, however the reported
     #       lint violation make a lot of sense so we should re-enable the lints below and work to fix the findings
     - perfsprint
+    - tenv  # the functionality provided by 'usetesting'