Fix Vale issues for ./administration/auth/oidc.md

The following issues occurred when we ran a linting tool called Vale against this topic. To fix the issues, open a merge request for the markdown file, which you'll find in the /doc directory. The first number on each line indicates the line number.

If you feel any of these warnings are incorrect, feel free to create an issue with the tw-test label so we can improve our Vale tests.

| 13:20:gitlab.FutureTense:Avoid using future tense: "will provide". Use present tense instead. |
| 89:44:gitlab.FutureTense:Avoid using future tense: "will be". Use present tense instead.      |
| 90:59:gitlab.FutureTense:Avoid using future tense: "will be". Use present tense instead.      |
| 94:67:gitlab.FutureTense:Avoid using future tense: "will try". Use present tense instead.     |
| 100:26:gitlab.FutureTense:Avoid using future tense: "will POST". Use present tense instead.   |
| 102:98:gitlab.FutureTense:Avoid using future tense: "will be". Use present tense instead.     |
| 103:141:gitlab.FutureTense:Avoid using future tense: "will use". Use present tense instead.   |
| 122:81:gitlab.FutureTense:Avoid using future tense: "will ask". Use present tense instead.    |
| 124:1:gitlab.FutureTense:Avoid using future tense: "will be". Use present tense instead.      |
| 124:34:gitlab.FutureTense:Avoid using future tense: "will be". Use present tense instead.     |
| 161:88:gitlab.FutureTense:Avoid using future tense: "you'll need". Use present tense instead. |